Faustin,
Thanks for looking into this, and for your work packaging MariaDB for
Debian.
It looks to me like https://jira.mariadb.org/browse/MDEV-29988 is very
likely to be the issue we're seeing. Fortunately (if I'm interpreting
upstream's JIRA correctly), it looks like a fix exists and will be
included in 10.5.19.
From their release history, 10.5.19 can be expected in early February.
Probably what I will do is downgrade all machines to 10.5.15 and look
forward to the Debian package of 10.5.19, which hopefully will not be
long after the upstream release.
