Turning on concert pitch for the score and leaving transposed pitch for parts of transposing instruments corrupts these parts

Steps to reproduce:
1. Create score with at leas one transposing instrument
2. Create part for this instrument
3. Set the score to concert pitch and the part to transposed pitch
4. Save the file and close MuseScore
5. Reopen the file

Expected behavior: The score is set to concert pitch, the part is set to transposed pitch
Actual behavior: The score is set to concert pitch, the part is also set to concert pitch, has notes from concert pitch but key signature from transposed pitch
EDIT: The notes, technically, are still correct, but in the incorrect key, and if you keep repeating these steps 12 times* you end up with the original score
*or less, when the instrument transposes by the number of fifths which is a divisor of 12

Workaround:
When closing the file, either set all parts to concert pitch or all to transposed.

Version number: musescore 3.0.5-1 on Arch Linux

Surprisingly, the issue is not present when setting the part to concert pitch and the score to transposed pitch.