Diff of the two buildlogs:

--
--- b1/build.log	2024-05-20 02:58:46.600952996 +0000
+++ b2/build.log	2024-05-20 03:03:10.145742625 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Sun May 19 14:56:01 -12 2024
-I: pbuilder-time-stamp: 1716173761
+I: Current time: Sun Jun 22 23:21:48 +14 2025
+I: pbuilder-time-stamp: 1750584108
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/unstable-reproducible-base.tgz]
 I: copying local configuration
@@ -26,52 +26,84 @@
 dpkg-source: info: unpacking cppnumericalsolvers_1.0.0-2.debian.tar.xz
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/3572915/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/2106969/tmp/hooks/D01_modify_environment starting
+debug: Running on codethink03-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 Jun 22 09:21 /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/2106969/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/2106969/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]="21" [3]="1" [4]="release" [5]="aarch64-unknown-linux-gnu")
+  BASH_VERSION='5.2.21(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='09a4917cd5b74906a75dc9ce63ce2a0d'
-  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='3572915'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=5c3540eeb5144215983180faca18acc5
+  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=2106969
   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.G113yvvt/pbuilderrc_pFLE --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.G113yvvt/b1 --logfile b1/build.log cppnumericalsolvers_1.0.0-2.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.G113yvvt/pbuilderrc_VBYf --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.G113yvvt/b2 --logfile b2/build.log cppnumericalsolvers_1.0.0-2.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 codethink02-arm64 6.1.0-21-cloud-arm64 #1 SMP Debian 6.1.90-1 (2024-05-03) aarch64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-21-cloud-arm64 #1 SMP Debian 6.1.90-1 (2024-05-03) aarch64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 May 19 07:42 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/3572915/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Jun 21 14:06 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/2106969/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -153,7 +185,7 @@
 Get: 40 http://deb.debian.org/debian unstable/main arm64 pkg-config arm64 1.8.1-1+b2 [14.0 kB]
 Get: 41 http://deb.debian.org/debian unstable/main arm64 libeigen3-dev all 3.4.0-4 [1041 kB]
 Get: 42 http://deb.debian.org/debian unstable/main arm64 libgtest-dev arm64 1.14.0-1+b1 [241 kB]
-Fetched 20.7 MB in 0s (114 MB/s)
+Fetched 20.7 MB in 0s (108 MB/s)
 debconf: delaying package configuration, since apt-utils is not installed
 Selecting previously unselected package sensible-utils.
 (Reading database ... 
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(Reading database ... 100%
(Reading database ... 19763 files and directories currently installed.)
@@ -336,7 +368,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/cppnumericalsolvers-1.0.0/ && 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  > ../cppnumericalsolvers_1.0.0-2_source.changes
+I: user script /srv/workspace/pbuilder/2106969/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for unstable
+I: user script /srv/workspace/pbuilder/2106969/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/cppnumericalsolvers-1.0.0/ && 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  > ../cppnumericalsolvers_1.0.0-2_source.changes
 dpkg-buildpackage: info: source package cppnumericalsolvers
 dpkg-buildpackage: info: source version 1.0.0-2
 dpkg-buildpackage: info: source distribution unstable
@@ -358,10 +394,10 @@
 [----------] Global test environment set-up.
 [----------] 2 tests from GradientDescentTest
 [ RUN      ] GradientDescentTest.RosenbrockFarValue
-[       OK ] GradientDescentTest.RosenbrockFarValue (1 ms)
+[       OK ] GradientDescentTest.RosenbrockFarValue (2 ms)
 [ RUN      ] GradientDescentTest.RosenbrockNearValue
 [       OK ] GradientDescentTest.RosenbrockNearValue (0 ms)
-[----------] 2 tests from GradientDescentTest (1 ms total)
+[----------] 2 tests from GradientDescentTest (2 ms total)
 
 [----------] 3 tests from ConjugatedGradientDescentTest
 [ RUN      ] ConjugatedGradientDescentTest.RosenbrockFarValue
@@ -403,8 +439,8 @@
 
 [----------] 1 test from CMAesTest
 [ RUN      ] CMAesTest.RosenbrockNearValue
-[       OK ] CMAesTest.RosenbrockNearValue (3 ms)
-[----------] 1 test from CMAesTest (3 ms total)
+[       OK ] CMAesTest.RosenbrockNearValue (2 ms)
+[----------] 1 test from CMAesTest (2 ms total)
 
 [----------] 3 tests from NelderMeadTest/0, where TypeParam = float
 [ RUN      ] NelderMeadTest/0.RosenbrockFarValue
@@ -526,8 +562,8 @@
 
 [----------] 1 test from CMAesTest/0, where TypeParam = float
 [ RUN      ] CMAesTest/0.RosenbrockNearFull
-[       OK ] CMAesTest/0.RosenbrockNearFull (4 ms)
-[----------] 1 test from CMAesTest/0 (4 ms total)
+[       OK ] CMAesTest/0.RosenbrockNearFull (1 ms)
+[----------] 1 test from CMAesTest/0 (1 ms total)
 
 [----------] 1 test from CMAesTest/1, where TypeParam = double
 [ RUN      ] CMAesTest/1.RosenbrockNearFull
@@ -536,13 +572,13 @@
 
 [----------] 1 test from CMAesBTest/0, where TypeParam = float
 [ RUN      ] CMAesBTest/0.RosenbrockNearFull
-[       OK ] CMAesBTest/0.RosenbrockNearFull (0 ms)
-[----------] 1 test from CMAesBTest/0 (0 ms total)
+[       OK ] CMAesBTest/0.RosenbrockNearFull (4 ms)
+[----------] 1 test from CMAesBTest/0 (4 ms total)
 
 [----------] 1 test from CMAesBTest/1, where TypeParam = double
 [ RUN      ] CMAesBTest/1.RosenbrockNearFull
-[       OK ] CMAesBTest/1.RosenbrockNearFull (2 ms)
-[----------] 1 test from CMAesBTest/1 (2 ms total)
+[       OK ] CMAesBTest/1.RosenbrockNearFull (0 ms)
+[----------] 1 test from CMAesBTest/1 (0 ms total)
 
 [----------] 2 tests from CentralDifference/0, where TypeParam = float
 [ RUN      ] CentralDifference/0.Gradient
@@ -559,7 +595,7 @@
 [----------] 2 tests from CentralDifference/1 (0 ms total)
 
 [----------] Global test environment tear-down
-[==========] 62 tests from 26 test suites ran. (20 ms total)
+[==========] 62 tests from 26 test suites ran. (18 ms total)
 [  PASSED  ] 62 tests.
 rm -f ./verify
 make[1]: Leaving directory '/build/reproducible-path/cppnumericalsolvers-1.0.0'
@@ -588,12 +624,14 @@
 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/2106969/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/2106969/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/3572915 and its subdirectories
-I: Current time: Sun May 19 14:58:45 -12 2024
-I: pbuilder-time-stamp: 1716173925
+I: removing directory /srv/workspace/pbuilder/2106969 and its subdirectories
+I: Current time: Sun Jun 22 23:26:07 +14 2025
+I: pbuilder-time-stamp: 1750584367