Diff of the two buildlogs:

--
--- b1/build.log	2025-01-26 21:21:45.377309982 +0000
+++ b2/build.log	2025-01-26 21:52:39.553656504 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Sat Feb 28 15:37:00 -12 2026
-I: pbuilder-time-stamp: 1772336220
+I: Current time: Mon Jan 27 11:21:48 +14 2025
+I: pbuilder-time-stamp: 1737926508
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/unstable-reproducible-base.tgz]
 I: copying local configuration
@@ -22,52 +22,84 @@
 dpkg-source: info: unpacking flox_0.10.0-1.debian.tar.xz
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/4109263/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/D01_modify_environment starting
+debug: Running on codethink04-arm64.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Jan 26 21:21 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='arm64'
-  DEBIAN_FRONTEND='noninteractive'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="37" [3]="1" [4]="release" [5]="aarch64-unknown-linux-gnu")
+  BASH_VERSION='5.2.37(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=arm64
+  DEBIAN_FRONTEND=noninteractive
   DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=12 '
-  DISTRIBUTION='unstable'
-  HOME='/root'
-  HOST_ARCH='arm64'
+  DIRSTACK=()
+  DISTRIBUTION=unstable
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=aarch64
+  HOST_ARCH=arm64
   IFS=' 	
   '
-  INVOCATION_ID='c4b9ff95104440c99d9add22a2aa1bab'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='4109263'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=66cc78290a834379a7b08bca6af7b01b
+  LANG=C
+  LANGUAGE=nl_BE:nl
+  LC_ALL=C
+  MACHTYPE=aarch64-unknown-linux-gnu
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnu
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=2927688
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.JYGiHu7q/pbuilderrc_AdPb --distribution unstable --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.JYGiHu7q/b1 --logfile b1/build.log flox_0.10.0-1.dsc'
-  SUDO_GID='109'
-  SUDO_UID='104'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://192.168.101.4:3128'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.JYGiHu7q/pbuilderrc_3uaa --distribution unstable --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.JYGiHu7q/b2 --logfile b2/build.log flox_0.10.0-1.dsc'
+  SUDO_GID=109
+  SUDO_UID=104
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://192.168.101.4:3128
 I: uname -a
-  Linux codethink03-arm64 6.1.0-30-cloud-arm64 #1 SMP Debian 6.1.124-1 (2025-01-12) aarch64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-30-cloud-arm64 #1 SMP Debian 6.1.124-1 (2025-01-12) aarch64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/4109263/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -252,7 +284,7 @@
 Get: 109 http://deb.debian.org/debian unstable/main arm64 python3-scipy arm64 1.14.1-3 [18.5 MB]
 Get: 110 http://deb.debian.org/debian unstable/main arm64 python3-setuptools-scm all 8.1.0-1 [40.5 kB]
 Get: 111 http://deb.debian.org/debian unstable/main arm64 python3-xarray all 2025.01.1-1 [800 kB]
-Fetched 71.2 MB in 0s (153 MB/s)
+Fetched 71.2 MB in 1s (58.8 MB/s)
 Preconfiguring packages ...
 Selecting previously unselected package libpython3.13-minimal:arm64.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19946 files and directories currently installed.)
@@ -621,8 +653,8 @@
 Setting up tzdata (2025a-1) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Sun Mar  1 03:37:22 UTC 2026.
-Universal Time is now:  Sun Mar  1 03:37:22 UTC 2026.
+Local time is now:      Sun Jan 26 21:23:02 UTC 2025.
+Universal Time is now:  Sun Jan 26 21:23:02 UTC 2025.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up autotools-dev (20220109.1) ...
@@ -727,7 +759,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/flox-0.10.0/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../flox_0.10.0-1_source.changes
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for unstable
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/flox-0.10.0/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../flox_0.10.0-1_source.changes
 dpkg-buildpackage: info: source package flox
 dpkg-buildpackage: info: source version 0.10.0-1
 dpkg-buildpackage: info: source distribution unstable
@@ -803,7 +839,7 @@
 Copying flox.egg-info to build/bdist.linux-aarch64/wheel/./flox-0.10.0.egg-info
 running install_scripts
 creating build/bdist.linux-aarch64/wheel/flox-0.10.0.dist-info/WHEEL
-creating '/build/reproducible-path/flox-0.10.0/.pybuild/cpython3_3.12_flox/.tmp-cl6yerhd/flox-0.10.0-py3-none-any.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
+creating '/build/reproducible-path/flox-0.10.0/.pybuild/cpython3_3.12_flox/.tmp-ymr6ql7v/flox-0.10.0-py3-none-any.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
 adding 'flox/__init__.py'
 adding 'flox/_version.py'
 adding 'flox/aggregate_flox.py'
@@ -868,7 +904,7 @@
 Copying flox.egg-info to build/bdist.linux-aarch64/wheel/./flox-0.10.0.egg-info
 running install_scripts
 creating build/bdist.linux-aarch64/wheel/flox-0.10.0.dist-info/WHEEL
-creating '/build/reproducible-path/flox-0.10.0/.pybuild/cpython3_3.13_flox/.tmp-gsol22th/flox-0.10.0-py3-none-any.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
+creating '/build/reproducible-path/flox-0.10.0/.pybuild/cpython3_3.13_flox/.tmp-faqt94om/flox-0.10.0-py3-none-any.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
 adding 'flox/__init__.py'
 adding 'flox/_version.py'
 adding 'flox/aggregate_flox.py'
@@ -976,40 +1012,20 @@
 
 tests/test_properties.py::test_first_last
 tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
 tests/test_properties.py::test_first_last_useless
   /build/reproducible-path/flox-0.10.0/tests/strategies.py:65: CFWarning: this date/calendar/year zero convention is not supported by CF
     return cftime.num2date(values, units=unit, calendar=cal)
 
 tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
   /usr/lib/python3/dist-packages/dask/tokenize.py:242: CFWarning: this date/calendar/year zero convention is not supported by CF
     mod.loads(out, buffers=buffers)
 
-tests/test_properties.py: 32 warnings
-  /usr/lib/python3/dist-packages/dask/array/core.py:5083: CFWarning: this date/calendar/year zero convention is not supported by CF
-    result = function(*args, **kwargs)
-
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-tests/test_properties.py::test_first_last
-  /build/reproducible-path/flox-0.10.0/flox/core.py:2712: CFWarning: this date/calendar/year zero convention is not supported by CF
-    result = _to_pytimedelta(result, unit="us") + offset
-
 -- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
-= 2088 passed, 2287 skipped, 7753 deselected, 108 xfailed, 3 xpassed, 1021 warnings in 195.82s (0:03:15) =
+= 2088 passed, 2287 skipped, 7753 deselected, 108 xfailed, 3 xpassed, 976 warnings in 771.68s (0:12:51) =
 I: pybuild base:311: cd /build/reproducible-path/flox-0.10.0/.pybuild/cpython3_3.13_flox/build; python3.13 -m pytest --ignore=/build/reproducible-path/flox-0.10.0/tests/test_asv.py -k "not test_xarray_reduce_single_grouper and not test_func_is_aggregation and not test_groupby_bins_indexed_coordinate and not test_groupby_reduce_all and not test_verify_complex_cohorts and not test_group_by_datetime and not test_find_group_cohorts and not test_cohorts_map_reduce_consistent_dtypes and not test_dtype_accumulation and not test_multi_index_groupby_sum and not test_find_cohorts_missing_groups and not test_snapshot_cohorts and not test_groupby_reduce and not test_scans and not test_ffill_bfill_reverse and not test_groupby_preserve_dtype and not test_blockwise_avoid_rechunk" /build/reproducible-path/flox-0.10.0/tests
 ============================= test session starts ==============================
 platform linux -- Python 3.13.1, pytest-8.3.4, pluggy-1.5.0
@@ -1091,11 +1107,16 @@
     ret[i] = func(grp)
 
 tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
+tests/test_properties.py::test_first_last_useless
   /build/reproducible-path/flox-0.10.0/tests/strategies.py:65: CFWarning: this date/calendar/year zero convention is not supported by CF
     return cftime.num2date(values, units=unit, calendar=cal)
 
 -- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
-= 2088 passed, 2287 skipped, 7753 deselected, 108 xfailed, 3 xpassed, 969 warnings in 180.81s (0:03:00) =
+= 2088 passed, 2287 skipped, 7753 deselected, 108 xfailed, 3 xpassed, 974 warnings in 709.32s (0:11:49) =
    create-stamp debian/debhelper-build-stamp
    dh_testroot -O--buildsystem=pybuild
    dh_prep -O--buildsystem=pybuild
@@ -1128,12 +1149,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: including full source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/2927688/tmp/hooks/B01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/4109263 and its subdirectories
-I: Current time: Sat Feb 28 15:44:43 -12 2026
-I: pbuilder-time-stamp: 1772336683
+I: removing directory /srv/workspace/pbuilder/2927688 and its subdirectories
+I: Current time: Mon Jan 27 11:52:38 +14 2025
+I: pbuilder-time-stamp: 1737928358