Some custom shortcuts no longer work in Windows 10, MuseScore 3.x
Problem: Create a custom shortcut for "Beam start" via the Settings-Shortcuts menu to separate beams faster.
No longer works on Windows (10 20H2). It still works on the Mac.
I've used this since MuseScore 2 and need it quite often (in combination with a beam middle shortcut to join beams).
Starting with version 3.x (unfortunately I don't remember exactly from which version) it stopped working. I tried several key combinations to exclude that it was because of that, e.g. Ctrl+Shift+8 [= "(" at the German layout], umlauts, etc.
As a workaround you have to use the palette and drag+drop "Beam start". This slows down the workflow considerably.