Mobile and PC edits not aligned

This seems to be happening quite frequently, I use both LR on my iPad and phone and LrC on my desktop.

Files seem to lose sync on a regular basis and shots I've had edited a long time ago (could even just be PC-only edits) seem to "reset" and lose my final version on desktop. The only way I've found to recover is if LR on my iPad / phone has a Version history to be able to go back and apply the edited version to replace it having been reverted back to the unedited file.

Any ideas what is causing a large number of files to revert back to their original state only on LrC?

I'm on Windows
LrC V13.1