That was a nice one
https://github.com/discourse/discourse/pull/36870
The issue was that we were automatically increasing the public_version of a post, even we were going to hide the revision later in the process because a staff member added a hidden tag.
What made it somewhat harder to “track” was that we would fix the public_version later when the PostRevision.ensure_consistency! runs (it’s scheduled to run every 12 hours).