I’m having the same problem in 10.0.5. I have some titles that were typed up quickly, with typos and lacking punctuation and line breaks. I have edited them several times, they always revert back. They revert back as soon as I start doing something else, without restarting Final Cut. I have restarted the programme and the computer, but the problem persists. I’ll have a look at that undo bug you mention, but does anyone have any solutions for this?