Wrong base value used for duplet in some time signatures
My case is similar:
1) new score, 5/4
2) select a full measure rest
Result: a duplet of two quarters, which seems way too short of a note value to fill a 5/4 measure.
I get that sometimes there can be debate about what note value to use for a given tuplet. Like, in 5/4, should a full measure triplet be represented as three halves or three quarters (do we round up or down). But I can't think of any reason for a full measure duplet in 5/4 to only use quarters. The choice should be two halves or two wholes, maybe two dotted halves if you're into that sort of thing.
Oddly, Ctrl+4 yields four quarters. Odd in that we somehow end up using the same note value for a duplet as a quadruplet of the same duration. On the other hand, no corruption - the ratio reports as 2:5 and 4:5 respectively. So not a huge deal.
Bug exists in 2.1, 2.2.1, and still exists in my fairly-current build of 2.3. So it's survived the turmoil over different tuplet reduction schemes :-)