Fretboard diagrams: barré applied wrongly if there is another dot already at same position

OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.0.3.5341, revision: e06ea8e

1. Click on 6th string, fret 3, say:
   
2. Now Shift + click on string 4, fret 3.

Expected result: Partial barré and separate dot at same position:

Actual result: Barré wrongly extends all the way to the left-most dot:

See also: #283676: Fretboard diagrams: barré deleted when separate dot is added afterwards at same position. Related to #283681: [EPIC] Fretboard diagram issues.