Marching Snare Ninelets
Just a random bug that I found, MuseScore crashes any time that I try to do two beats of ninelets on a marching snare line. It places the first set perfectly on beat one, then as soon as I hit ctrl-9 to place the second set, the program crashes. Definitely a weird bug. I have found that if I select the first set of ninelets and copy/paste, it works fine. So there's at least a workaround to make it work until the bug is fixed.
Comments
It crashes when you try to create a ninelet with one of the notes/rests of the previous ninelet selected (so for a ninelet inside a ninelet) or if the duration still is set to 32nd, which would result in durations that are too short for MuseScore to handle, instead you need to select the next quarter note/rest or the corresponding duration.
MuseScore shouldn't crash on this though, so this certainly is a bug, now reported in #268293: Creating a 9-let or 8-let from a 32nd note/rest causes crash
So to be clear: while it is true that MuseScore shouldn't crash if you press Ctrl+( with the 32nd duration still selected, this also isn't the right way to get the result you want. You need to reselect quarter note (or whatever) as the full duration for the tuplet before pressing Ctrl+9.