Copy-pasted sextuplets contain 7 notes, deleting them crashes MuseScore

I'm the using 3.1 Beta release on Windows 10

Steps to reproduce:
-In any score, select any rest or note value and create a sextuplet.
-select the sextuplet, copy it and paste it somewhere else.

Expected behavior:
-Pasted sextuplet has 6 notes

Actual behavior:
-pasted sextuplet has 7 notes

Steps to crash musescore:
-Save the file, and reopen it (notice the copied sextuplet is also corrupted)
-select the pasted sextuplet, press delete

Expected behavior:
-no change from last opening of save file
-sextuplet is deleted

Actual behavior:
-all sextuplets are corrupted, pasted ones are differently corrupted
-musescore crashes

Notes:
if you make sextuplets and don't copy paste them, when you save the file and reopen it, the sextuplets will be corrupted in the same way. Deleting these will not crash the program.