Acciaccaturas in transposing instruments get wrong pitch

If you save a score containing acciaccaturas on a transposing instrument and then reload it, the pitches of the acciaccaturas are wrong.

Version: Musescore version 2.9.5, revision 2012, Mac OS X.

Steps to reproduce:

1. Create a new score, and add one instrument, a Bb tenor sax. (It can be any transposing instrument, but the problem is more obvious with instruments that transpose by a larger interval.)
2. Enter an A semibreve in the middle of the clef.
3. Add a B acciaccatura to the A, one tone above.
4. Confirm that both notes play back at the expected pitch by clicking on them.
5. Save the score and close it.
6. Reopen the score.
7. Observe that the A plays back at the expected pitch, but the B acciaccatura plays back a major ninth higher than it should. This incidentally is the same interval by which the Bb tenor sax transposes.