Grace note properties aren't linked between score and parts
In a score with multiple parts, if in the main score is added a grace note, then marked as invisible, without stem and not playable, these grace note's properties aren't synchronized in the parts nor the other way around (from the part to the main score).
If a new part is created, the properties are duplicated correctly. It doesn't work for already existing parts. As some parts have different styles and line breaks than the main score, it's not a simple matter of recreating the part (and also because the altered grace note properties on the part isn't reflected on the main score).
I detected this bug on version 2.3.1 (OS: Windows , Arch.: x86_64, MuseScore version (32-bit): 2.3.1, revision: 0899e9d), while attempting to workaround the slur and tie endings not appearing on the second volta (create a grace note on the second volta, mark it invisible and unplayable, then add the tie or the slur).