Crash caused by incorrect mapping of voices between parts and master score
There are several ways to reproduce the issue, here is one of the most minimal:
1) New score, treble clef.
2) File→Parts, add a part for the second voice.
3) Switch to part, enter a note in the first beat (N→A).
In fact, unexpected things begin already here: the part should be mapped to the second voice but the note appears in the first voice in master score.
4) Switch to master score, enter a note in the first beat (N→B).
5) Switch to part, enter a note in the first beat (N→C).
It is important for reproducing to replace notes rather than add them to chord (that is why I described keystrokes here), otherwise this crash doesn't occur (though the results are still not correct).