We have seen this previously on Debian Buster and thought it was only there, but it seems not. That suggests it’s likely the newest version of a component or components not working correctly, probably MariaDB 10.4 and DBD::mysql. We submitted a failing test case to the DBD-mysql project that seems to point to the underlying issue. Pending a fix for that, we may need to pick an earlier version of DBD-mysql or look into a work-around.
@GreenJimll Are you able to reproduce this with MariaDB 10.3?