Measure number size in parts is bugged

Measure number size in parts are a bit buggy. I'm trying to change measure number size in parts, but it doesn't want to save and reverts back to what the score size is set to. BUT, it's inconsistent. It differs whether you have only one part created, or multiple parts created. I haven't been able to pinpoint where it goes wrong exactly. All l'm fairly certain of is that measure number size in parts should not be linked to the score.

I've uploaded a test score to mess with this on, but unfortunately, I can't consistently pinpoint what the problem is exactly. When you have one part, it seems like measure numbers are linked to the score. But, when there is more than one part, this changes in more ways than one. I've tried changing the size in score only, in both score and part, in part only... I've tried resetting measure number size to program default (whatever is original default style size before you first change it).

This need more info than I'm willing to look into at this time. Maybe I'll give it another shot sometime soon, but I'm rather confused from trying right now. For a workaround, I just save the part as a separate file and work on it like a score.