Wrong tuplet denominator chosen automatically

If I hit ctrl-4 on a 7-beat note or rest (bar 1 of the enclosed) I don't get the expected tuplet (bar 2) but a bunch of double-dotted notes (bar 3). To get the tuplet I have to choose 'other' from the tuplet menu and enter 7 as the ratio denominator.

If I hit ctrl-4 on a 5-beat note or rest (bar 4), I don't get the tuplet (bar 5), in fact I don't get anything but an error message because musescore has failed to recognise that this is a five-beat note, and has automatically chosen the wrong denominator. I have to go to 'other' and choose 5 myself.

If I create a duplet over 5 eighth notes (bar 7) I should get two quarter notes (bar 8; duration of each is more than a quarter note). Instead I get two eighth notes (bar 9).

Even over 6 beats (bars 11-13) strange things happen, although 3 seems to be handled properly (bar14).