Diff of the two buildlogs:

--
--- b1/build.log	2025-01-28 05:21:12.051414768 +0000
+++ b2/build.log	2025-01-28 05:25:07.968754570 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Sun Mar  1 23:43:12 -12 2026
-I: pbuilder-time-stamp: 1772451792
+I: Current time: Tue Jan 28 19:21:15 +14 2025
+I: pbuilder-time-stamp: 1738041675
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -24,52 +24,84 @@
 dpkg-source: info: applying skip-tests-for-big-endian.patch
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/2565545/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/268377/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos1-amd64.
+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 28 05:21 /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/268377/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/268377/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='amd64'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=42 '
-  DISTRIBUTION='trixie'
-  HOME='/root'
-  HOST_ARCH='amd64'
+  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]="x86_64-pc-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=amd64
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=20 '
+  DIRSTACK=()
+  DISTRIBUTION=trixie
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=x86_64
+  HOST_ARCH=amd64
   IFS=' 	
   '
-  INVOCATION_ID='8349ffb79d4844cab1779c790d65fa16'
-  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='2565545'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=faf1df9fb39c4e8b83752b62515fe8d6
+  LANG=C
+  LANGUAGE=et_EE:et
+  LC_ALL=C
+  MACHTYPE=x86_64-pc-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=268377
   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.L3W7K7td/pbuilderrc_m0vY --distribution trixie --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.L3W7K7td/b1 --logfile b1/build.log libpdl-netcdf-perl_4.25-1.dsc'
-  SUDO_GID='110'
-  SUDO_UID='105'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://213.165.73.152:3128'
+  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.L3W7K7td/pbuilderrc_cu36 --distribution trixie --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.L3W7K7td/b2 --logfile b2/build.log libpdl-netcdf-perl_4.25-1.dsc'
+  SUDO_GID=110
+  SUDO_UID=105
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://46.16.76.132:3128
 I: uname -a
-  Linux ionos5-amd64 6.12.9+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.9-1~bpo12+1 (2025-01-19) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-30-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.124-1 (2025-01-12) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/2565545/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/268377/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -232,7 +264,7 @@
 Get: 114 http://deb.debian.org/debian trixie/main amd64 libpod-parser-perl all 1.67-1 [94.1 kB]
 Get: 115 http://deb.debian.org/debian trixie/main amd64 libterm-readkey-perl amd64 2.38-2+b4 [24.6 kB]
 Get: 116 http://deb.debian.org/debian trixie/main amd64 pdl amd64 1:2.099-1 [3103 kB]
-Fetched 60.1 MB in 1s (90.0 MB/s)
+Fetched 60.1 MB in 23s (2629 kB/s)
 Preconfiguring packages ...
 Selecting previously unselected package sensible-utils.
 (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 ... 19855 files and directories currently installed.)
@@ -714,7 +746,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/libpdl-netcdf-perl-4.25/ && 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  > ../libpdl-netcdf-perl_4.25-1_source.changes
+I: user script /srv/workspace/pbuilder/268377/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/268377/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/libpdl-netcdf-perl-4.25/ && 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  > ../libpdl-netcdf-perl_4.25-1_source.changes
 dpkg-buildpackage: info: source package libpdl-netcdf-perl
 dpkg-buildpackage: info: source version 4.25-1
 dpkg-buildpackage: info: source distribution unstable
@@ -739,7 +775,7 @@
    debian/rules override_dh_auto_build
 make[1]: Entering directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 LD_RUN_PATH="" dh_auto_build
-	make -j42
+	make -j20
 make[2]: Entering directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 "/usr/bin/perl" "-I/usr/lib/x86_64-linux-gnu/perl5/5.40" "-MPDL::PP=PDL::NetCDF,PDL::NetCDF,NetCDF,,," netcdf.pd
 Running Mkbootstrap for NetCDF ()
@@ -880,7 +916,7 @@
    debian/rules override_dh_auto_test
 make[1]: Entering directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 TEST_VERBOSE=1 DISPLAY="" dh_auto_test
-	make -j42 test TEST_VERBOSE=1
+	make -j20 test TEST_VERBOSE=1
 make[2]: Entering directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 "/usr/bin/perl" -MExtUtils::Command::MM -e 'cp_nonempty' -- NetCDF.bs blib/arch/auto/PDL/NetCDF/NetCDF.bs 644
 PERL_DL_NONLAZY=1 "/usr/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(1, 'blib/lib', 'blib/arch')" t/*.t
@@ -950,8 +986,8 @@
 ok 9 - got old format
 ok 10 - switching default-format
 ok 11 - An object of class 'PDL::NetCDF' isa 'PDL::NetCDF'
-ok 12 - /tmp/7V_9989boj/bar.nc4 is netcdf4
-ok 13 - /tmp/7V_9989boj/bar.nc4 is netcdf4
+ok 12 - /tmp/1v24_s6fwn/bar.nc4 is netcdf4
+ok 13 - /tmp/1v24_s6fwn/bar.nc4 is netcdf4
 ok 14 - put with deflate
 ok 15 - deflateShuffle for var1
 ok 16 - putslice with deflate
@@ -970,14 +1006,14 @@
 1..28
 ok
 All tests successful.
-Files=2, Tests=79,  0 wallclock secs ( 0.03 usr  0.00 sys +  0.29 cusr  0.06 csys =  0.38 CPU)
+Files=2, Tests=79,  2 wallclock secs ( 0.06 usr  0.02 sys +  0.75 cusr  0.15 csys =  0.98 CPU)
 Result: PASS
 make[2]: Leaving directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 make[1]: Leaving directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
    create-stamp debian/debhelper-build-stamp
    dh_prep
    dh_auto_install --destdir=debian/libpdl-netcdf-perl/
-	make -j42 install DESTDIR=/build/reproducible-path/libpdl-netcdf-perl-4.25/debian/libpdl-netcdf-perl AM_UPDATE_INFO_DIR=no PREFIX=/usr
+	make -j20 install DESTDIR=/build/reproducible-path/libpdl-netcdf-perl-4.25/debian/libpdl-netcdf-perl AM_UPDATE_INFO_DIR=no PREFIX=/usr
 make[1]: Entering directory '/build/reproducible-path/libpdl-netcdf-perl-4.25'
 "/usr/bin/perl" -MExtUtils::Command::MM -e 'cp_nonempty' -- NetCDF.bs blib/arch/auto/PDL/NetCDF/NetCDF.bs 644
 Manifying 1 pod document
@@ -1025,12 +1061,14 @@
 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/268377/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/268377/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/2565545 and its subdirectories
-I: Current time: Sun Mar  1 23:44:11 -12 2026
-I: pbuilder-time-stamp: 1772451851
+I: removing directory /srv/workspace/pbuilder/268377 and its subdirectories
+I: Current time: Tue Jan 28 19:25:07 +14 2025
+I: pbuilder-time-stamp: 1738041907