Multimeasure rests extend into other measures, through other parts of the score
Multimeasure rests can expand unnecessarily, and can display over other parts of the score.
The following use case taken from cadiz1 (https://musescore.org/en/node/279957) reproduces the issue:
1) Load attached score, select Continuous View
2) Click first note C top staff -> Ctrl + L -> Press Space bar (or "_ " for enter melisma) a good deal into the score
Note the initial mm rest (marked 3) continue to expand while you add space. (Also when you press Cmd-Z in between.)
3) Toggle to Page View
Result: the mm rest expands on multiple pages.
After Save/Close/Reload, the layout reverts as expected.