Crash after adding tremolo to unpitched staff
Steps to reproduce in the score:
Add a half note crash cymbal slurred to an 8th note crash cymbal on the next measure (as shown in the screenshot, particularly to staff 26)
Add a 32nd note tremolo to the half note.
OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 188.8.131.5237, revision: b5add95