Slide font corruption if it has objects in Enhanced Metafile Format
You copy object from PowerPoint for Windows desktop app and paste it to another slide as Enhanced Metafile Format. If you open the slide which has the EMF objects, you see characters are corrupted in the deck. This happens in PowerPoint for Microsoft 365 for Mac version 16.44(20121301) or later. Please fix this problem.
I had a similar phenomenon. It happened if EMF images contain half-width kana characters.
When I downgrade Powerpoint to the version 16.43 (20110804), nothing happened. So, I'm certain that the version 16.44(20121301) or later have something to do with the problem.