Bug: staccato in the bass clef influences the playback of the treble

That's because you have the same note in the treble and bass clefs. It is physically impossible to play a short note while also sustaining the same note on the same instrument, at least for most instruments. In fact, MuseScore cuts the note short even without the staccato - just not *as* short, so it's harder to notice. But try deleting the second and third chord and you'll see.

That said, sometimes it can be convenient notationally to pretend you can physically play a long and short note of the same pitch at once, and if you don't decide to eliminate the left hand note, you could simply set it to not play back using the Inspector.

For vocal or instrumental music with notes in different parts on the same staff using multiple voices, this can be more problematic, as it *is* physically possible for two vocalists or two different instruments sharing a staff to play the same note with different duration. There is an open issue regarding this: #12971: Same note in different voices and lengths plays only the length of the shortest note