Hello. This was reported as "important" because the release of trixie was very close at the time, but trixie was already released and this still will be RC for forky.
As announced here: https://lists.debian.org/debian-devel/2025/09/msg00372.html this bug will be raised to serious in a few weeks, along with all the others that I reported today in the same category. If you have not tried to reproduce the bug yet, we have now a wiki page explaining how to do that with several build systems: https://wiki.debian.org/qa.debian.org/FTBFS/Nocheck Thanks.