Barline Changes Not Working at Start of Pages
S4 - Minor
In a masterscore in page view, if the user changes the type of barline at the start of a page, that change is effected in the masterscore, but not in accompanying parts. If the (same) barline at the end of the previous page is edited in the masterscore, then the equivalent barline in the parts is affected.
This isn't necessarily a bug. BTW, in the future, when could you attach actual scores and precise steps to reproduce the problem? Your descriptions are pretty good, but sometimes they contain some assumptions that won't be obvious to all.
Barlines at the start of systems are special and can be controlled independently of the barline at the end of the previous system. It's the barline at the end of a bar that is considered the "real" barline, and that's what gets linked. The barline at the start of the system is the special one. And since the start of a system for the score is very likely not the start of the system for the part - and vice versa - it doens't make sense to link them. If you want to change the actual barline, do it from the end of the previous bar.
So assuming I'm understanding you correctly, this is not a bug but a feature - the ability to set a barline style at start of system independently of the end of the previous system, anbd systems are not the same between score and parts. But it's possible I'm misunderstanding something, which is why attaching an actual score and precise steps to reproduce the problem helps.