It work's ok in WinBB
If I had a piano roll on MacBB I could see what's happening.
If you have Reaper you could save as xml to Reaper and you will have the chord track then you could use https://forum.cockos.com/showthread.php?t=192481 or https://reaperblog.net/2016/04/instant-arpeggios-chords/ on any guitar vst to create strumming, chords and arpeggios. You could import the track back into BB.