There’s no undo, but Lexicon does make a backup of your Engine database before writing anything to it. See Backups and how to restore them
The odd part about these accents is that I keep fixing it for users and that works, but then for other users it breaks. I’m going in circles a bit about it
I’ll check next week what the situation is there and if I can improve it. I’ll report back.
Can you zip and send me that track in your first post? Important to zip it so the correct accents are maintained. Add a few more with accents if you can, will be helpful for testing.