just a thought that might help as a short term workaround. if you are exporting the BIAB tracks to your DAW have you tried opening the BIAB song in RealBand and exporting from there?

depends how much work you do in BIAB before you export as RB doesn't keep frozen tracks apparently but you can regenerate in RB much the same as BIAB them save as a seq file which is unchanging. may solve the problem in the short term.