Rehearsal Marks problems in Parts in Musescore Studio 4.3.1 - MacMini M1 Sonoma 14.5

1) I added a Rehearsal Mark on my main Score (which has piano and oboe). Worked as expected on the Main Score, but on the Oboe Part it is an empty box.

2) I added a Rehearsal Mark on my Oboe part, and it had problems. I was given two boxes, one normal size, one smaller. When I tried to type in the larger one, it vanished. I found that if I fussed around enough, something would stick in the box ... but then it would show my different attempts. The Rehearsal Mark then did carry through to the Main Score, but with all my different attempts.

Re #1 - in MS 4.3.0, Rehearsal Marks entered on the main score showed up successfully in Parts.

Re #2 - I've never tried creating a Rehearsal Mark in a Part before.

See screenshots and sample score attached.