HELP NEEDED: debuging a ppc64el autopkgtest failure involving polkitd?

Hi, I'm trying to debug an autopkgtest failure for debian-edu-config
against an e2fsprogs upload.  It's only happening on ppc64el[1].  And
the funny thing is that it passed on e2fsprogs 1.47.2-2, but failed on
e2fsprogs 1.47.2-3, and the only change was fixing a bug in the
fuse2fs.postrm script --- and from the logs, debian-edu-config doesn't
install fuse2fs.

[1] https://ci.debian.net/packages/d/debian-edu-config/testing/ppc64el/

The specific failure is very strange, and looks like it is a failure
in adding a group for polkitd:

Creating group 'polkitd' with GID 989.   <---- We created the polkitd group here
Creating user 'polkitd' (User for polkitd) with UID 989 and GID 989.
chown: invalid group: ‘root:polkitd’ <---------- Huh?!?!?

To see the full failing autopkgtest log[2], as well as a "good"
autopkgtest run[3], I've included links to them here.

[2] https://ci.debian.net/packages/d/debian-edu-config/testing/ppc64el/61390462/
[3] https://ci.debian.net/packages/d/debian-edu-config/testing/ppc64el/61375791/

As near as I can tell, the failing chown for an invalid group that was
*just* created two lines earlier in the long has nothing to do with
e2fsprogs, and from looking at the test artifacts the only *other*
difference other than the newer version of e2fsprogs is a different
version of debianutils:

diff -ru art-bad/testbed-packages art-good/testbed-packages
--- art-bad/testbed-packages    2025-06-12 17:54:09
+++ art-good/testbed-packages   2025-06-10 06:47:39
@@ -21,7 +21,7 @@
 dbus-user-session      1.16.2-2
 debconf        1.5.91
 debian-archive-keyring 2025.1
-debianutils    5.23.1
+debianutils    5.22
 dialog 1.3-20250116-1
 diffutils      1:3.10-4
 dpkg   1.22.20

.... but i don't see how debianutils could make a difference, either.

So this is a really big mystery.  I've cc'ed folks who are involved
with polkitd and debianutils, as well as sending this query to the
ppc64el developers, hoping that someone can give me a hint as to what
might be going on.    What am I missing?

Many thanks!!!

						- Ted