Dragging dynamics symbols from an empty measure into a multimeasure rest shuts down the program.
in the attached score, in the view for the violin part, attempt to drag the "mp" dynamic, as shown in the screenshot. MuseScore crashes when you attempt to do this.
OS: macOS 10.16, Arch.: x86_64, MuseScore version (64-bit): 188.8.131.522126096, revision: 465e7b6
Note: I was able to work around the issue by deleting the dynamic symbol and adding it where I wanted it. However, this was after MuseScore had crashed twice when I tried moving the symbol.