Struggling to see why reprotest job failed

I have a reprotest failure in this job for which I haven't been able to understand the reason for failure.

The job log only lists,

INFO:reprotest:build successful, copying artifacts
INFO:reprotest:copying /tmp/reprotest.INFjNU/artifacts-experiment-1/ back from virtual server's /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1
INFO:reprotest:Running diff: ['diff', '-ru', '/builds/charles05/gst-devtools1.0/debian/output/reprotest/control', '/builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1']
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/gir1.2-gstreamer1.0-validate_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/gir1.2-gstreamer1.0-validate_1.26.5-1+salsaci+20250915+1_amd64.deb differ
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/gstreamer1.0-validate-dbgsym_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/gstreamer1.0-validate-dbgsym_1.26.5-1+salsaci+20250915+1_amd64.deb differ
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/gstreamer1.0-validate_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/gstreamer1.0-validate_1.26.5-1+salsaci+20250915+1_amd64.deb differ
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/libgstvalidate-1.0-0-dbgsym_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/libgstvalidate-1.0-0-dbgsym_1.26.5-1+salsaci+20250915+1_amd64.deb differ
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/libgstvalidate-1.0-0-dev_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/libgstvalidate-1.0-0-dev_1.26.5-1+salsaci+20250915+1_amd64.deb differ
Binary files /builds/charles05/gst-devtools1.0/debian/output/reprotest/control/source-root/libgstvalidate-1.0-0_1.26.5-1+salsaci+20250915+1_amd64.deb and /builds/charles05/gst-devtools1.0/debian/output/reprotest/experiment-1/source-root/libgstvalidate-1.0-0_1.26.5-1+salsaci+20250915+1_amd64.deb differ
section_end:1757936811:step_script

Which wasn't helpful. I downloaded the control and experiment deb's from the artifacts area, and still couldn't understand what the problem is:

$ debdiff control.deb  experiment.deb 
File lists identical (after any substitutions)

No differences were encountered between the control files

Tried with diffoscope,

$ diffoscope control.deb experiment.deb 
--- control.deb
+++ experiment.deb
├── file list
│ @@ -1,3 +1,3 @@
│  -rw-r--r--   0        0        0        4 2025-09-15 12:31:15.000000 debian-binary
│  -rw-r--r--   0        0        0      852 2025-09-15 12:31:15.000000 control.tar.xz
│ --rw-r--r--   0        0        0    22132 2025-09-15 12:31:15.000000 data.tar.xz
│ +-rw-r--r--   0        0        0    22144 2025-09-15 12:31:15.000000 data.tar.xz
├── control.tar.xz
│ ├── control.tar
│ │ ├── file list
│ │ │ @@ -1,3 +1,3 @@
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:05.000000 ./
│ │ │ --rw-r--r--   0 root         (0) root         (0)      868 2025-09-15 11:46:05.000000 ./control
│ │ │ --rw-r--r--   0 root         (0) root         (0)      374 2025-09-15 11:46:05.000000 ./md5sums
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:49.000000 ./
│ │ │ +-rw-r--r--   0 root         (0) root         (0)      868 2025-09-15 11:46:49.000000 ./control
│ │ │ +-rw-r--r--   0 root         (0) root         (0)      374 2025-09-15 11:46:49.000000 ./md5sums
├── data.tar.xz
│ ├── data.tar
│ │ ├── file list
│ │ │ @@ -1,12 +1,12 @@
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:04.000000 ./
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:45:59.000000 ./usr/
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:45:59.000000 ./usr/lib/
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:45:59.000000 ./usr/lib/x86_64-linux-gnu/
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:04.000000 ./usr/lib/x86_64-linux-gnu/girepository-1.0/
│ │ │ --rw-r--r--   0 root         (0) root         (0)    35760 2025-09-15 11:45:56.000000 ./usr/lib/x86_64-linux-gnu/girepository-1.0/GstValidate-1.0.typelib
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:45:59.000000 ./usr/share/
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:45:59.000000 ./usr/share/doc/
│ │ │ -drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:00.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/
│ │ │ --rw-r--r--   0 root         (0) root         (0)      179 2025-09-15 11:45:59.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/changelog.Debian.gz
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:48.000000 ./
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:42.000000 ./usr/
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:42.000000 ./usr/lib/
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:42.000000 ./usr/lib/x86_64-linux-gnu/
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:48.000000 ./usr/lib/x86_64-linux-gnu/girepository-1.0/
│ │ │ +-rw-r--r--   0 root         (0) root         (0)    35760 2025-09-15 11:46:38.000000 ./usr/lib/x86_64-linux-gnu/girepository-1.0/GstValidate-1.0.typelib
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:42.000000 ./usr/share/
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:42.000000 ./usr/share/doc/
│ │ │ +drwxr-xr-x   0 root         (0) root         (0)        0 2025-09-15 11:46:43.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/
│ │ │ +-rw-r--r--   0 root         (0) root         (0)      179 2025-09-15 11:46:42.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/changelog.Debian.gz
│ │ │  -rw-r--r--   0 root         (0) root         (0)     9501 2025-08-07 18:09:12.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/changelog.gz
│ │ │  -rw-r--r--   0 root         (0) root         (0)    10834 2025-09-15 11:35:10.000000 ./usr/share/doc/gir1.2-gstreamer1.0-validate/copyright

The package files are all identical, aside from timestamps, but the data tarballs do differ in size. I unpacked those also and ran a directory comparison tool, which told me all the files within them are indeed identical. I did a listing of the tar file metadata and can only see timestamp differences, which seems inevitable AFAIU, since the builds don't happen at the same time.

Can anyone here help me understand the failure better?