Diff of the two buildlogs:

--
--- b1/build.log	2023-04-08 08:38:38.816474892 +0000
+++ b2/build.log	2023-04-08 08:40:01.773728027 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Fri May 10 03:00:46 -12 2024
-I: pbuilder-time-stamp: 1715353246
+I: Current time: Sat Apr  8 22:38:42 +14 2023
+I: pbuilder-time-stamp: 1680943122
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/bookworm-reproducible-base.tgz]
 I: copying local configuration
@@ -16,7 +16,7 @@
 I: copying [./golang-github-dylanmei-iso8601_0.1.0.orig.tar.gz]
 I: copying [./golang-github-dylanmei-iso8601_0.1.0-7.debian.tar.xz]
 I: Extracting source
-gpgv: Signature made Sun Nov 27 06:50:37 2022 -12
+gpgv: Signature made Mon Nov 28 08:50:37 2022 +14
 gpgv:                using RSA key B23862C415D6565A4E86CBD7579C160D4C9E23E8
 gpgv: Can't check signature: No public key
 dpkg-source: warning: cannot verify inline signature for ./golang-github-dylanmei-iso8601_0.1.0-7.dsc: no acceptable signature found
@@ -25,11 +25,20 @@
 dpkg-source: info: unpacking golang-github-dylanmei-iso8601_0.1.0-7.debian.tar.xz
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/17380/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/D01_modify_environment starting
+debug: Running on codethink16-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
+lrwxrwxrwx 1 root root 4 Jan  6 03:20 /bin/sh -> dash
+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/16795/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/D02_print_environment starting
 I: set
   BUILDDIR='/build'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
+  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=8'
@@ -39,38 +48,38 @@
   IFS=' 	
   '
   LANG='C'
-  LANGUAGE='en_US:en'
+  LANGUAGE='nl_BE:nl'
   LC_ALL='C'
   MAIL='/var/mail/root'
   OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
+  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'
-  PPID='17380'
+  PPID='16795'
   PS1='# '
   PS2='> '
   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.5dl3vZSN/pbuilderrc_dtaU --distribution bookworm --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/bookworm-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.5dl3vZSN/b1 --logfile b1/build.log golang-github-dylanmei-iso8601_0.1.0-7.dsc'
+  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.5dl3vZSN/pbuilderrc_YYV4 --distribution bookworm --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/bookworm-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.5dl3vZSN/b2 --logfile b2/build.log --extrapackages usrmerge golang-github-dylanmei-iso8601_0.1.0-7.dsc'
   SUDO_GID='117'
   SUDO_UID='110'
   SUDO_USER='jenkins'
   TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
+  TZ='/usr/share/zoneinfo/Etc/GMT-14'
   USER='root'
   USERNAME='root'
   _='/usr/bin/systemd-run'
   http_proxy='http://192.168.101.16:3128'
 I: uname -a
-  Linux codethink11-arm64 4.15.0-208-generic #220-Ubuntu SMP Mon Mar 20 14:28:12 UTC 2023 aarch64 GNU/Linux
+  Linux i-capture-the-hostname 4.15.0-208-generic #220-Ubuntu SMP Mon Mar 20 14:28:12 UTC 2023 aarch64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 May  9 04:48 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/17380/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Apr  6 00:25 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -146,7 +155,7 @@
 Get: 34 http://deb.debian.org/debian bookworm/main arm64 golang-src all 2:1.19~1 [5756 B]
 Get: 35 http://deb.debian.org/debian bookworm/main arm64 golang-go arm64 2:1.19~1 [45.0 kB]
 Get: 36 http://deb.debian.org/debian bookworm/main arm64 golang-any arm64 2:1.19~1 [5876 B]
-Fetched 93.3 MB in 4s (21.6 MB/s)
+Fetched 93.3 MB in 2s (56.3 MB/s)
 debconf: delaying package configuration, since apt-utils is not installed
 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 ... 19616 files and directories currently installed.)
@@ -304,8 +313,17 @@
 Writing extended state information...
 Building tag database...
  -> Finished parsing the build-deps
+Reading package lists...
+Building dependency tree...
+Reading state information...
+usrmerge is already the newest version (35).
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
 I: Building the package
-I: Running cd /build/golang-github-dylanmei-iso8601-0.1.0/ && 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  > ../golang-github-dylanmei-iso8601_0.1.0-7_source.changes
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/A99_set_merged_usr starting
+Re-configuring usrmerge...
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/A99_set_merged_usr finished
+hostname: Temporary failure in name resolution
+I: Running cd /build/golang-github-dylanmei-iso8601-0.1.0/ && 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  > ../golang-github-dylanmei-iso8601_0.1.0-7_source.changes
 dpkg-buildpackage: info: source package golang-github-dylanmei-iso8601
 dpkg-buildpackage: info: source version 0.1.0-7
 dpkg-buildpackage: info: source distribution unstable
@@ -324,48 +342,48 @@
    dh_auto_configure -O--buildsystem=golang
    dh_auto_build -O--buildsystem=golang
 	cd obj-aarch64-linux-gnu && go install -trimpath -v -p 8 github.com/dylanmei/iso8601
-internal/goos
-internal/goexperiment
-math/bits
+internal/goarch
 internal/unsafeheader
-internal/itoa
-runtime/internal/syscall
+internal/goexperiment
+internal/goos
 internal/cpu
-internal/goarch
+internal/itoa
+math/bits
 unicode/utf8
-internal/race
-sync/atomic
+runtime/internal/syscall
 internal/abi
 runtime/internal/math
 runtime/internal/sys
+internal/race
+sync/atomic
 unicode
-math
-internal/bytealg
 runtime/internal/atomic
+internal/bytealg
+math
 runtime
 internal/reflectlite
 sync
 internal/testlog
 errors
 sort
-internal/oserror
+io
 internal/safefilepath
 path
-io
+internal/oserror
 strconv
 syscall
 bytes
 strings
 reflect
 regexp/syntax
-internal/syscall/execenv
 internal/syscall/unix
+internal/syscall/execenv
 time
 regexp
-io/fs
 internal/poll
-os
+io/fs
 internal/fmtsort
+os
 fmt
 github.com/dylanmei/iso8601
    dh_auto_test -O--buildsystem=golang
@@ -375,7 +393,7 @@
 === RUN   Test_format_duration
 --- PASS: Test_format_duration (0.00s)
 PASS
-ok  	github.com/dylanmei/iso8601	0.003s
+ok  	github.com/dylanmei/iso8601	0.005s
    create-stamp debian/debhelper-build-stamp
    dh_testroot -O--buildsystem=golang
    dh_prep -O--buildsystem=golang
@@ -403,12 +421,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: not including original source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/16795/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/16795/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/17380 and its subdirectories
-I: Current time: Fri May 10 03:01:37 -12 2024
-I: pbuilder-time-stamp: 1715353297
+I: removing directory /srv/workspace/pbuilder/16795 and its subdirectories
+I: Current time: Sat Apr  8 22:40:00 +14 2023
+I: pbuilder-time-stamp: 1680943200