Just installed the new 833 update to bb2021. It has not solved the problem. Still getting saw-tooth waves in real tracks which cause pops. The styles seem to play ok in the Style selector tab, but once I apply them to a chord sequence the problem appears - it is there when I play the song in bb prior to rendering. Once I render the files I can find the offending saw-tooth waves which coincide with the pops. So I think the problem is something in the bb 'file generating' code.