So my systems recently updated to rsync 3.4.3, and as soon as that happened my backup system - which does incremental backups using multiple --compare-dest= arguments - started to fail on anything but a full backup.

Revert to 3.4.1 and it works.

So I go look at the source in GitHub to see what might have changed, because there doesn't seem to be anything relevant in the changelog.

Since 3.4.1, 36 commits by "tridge and claude"

Oh for fuck's sakes.