Does unpairing them fix the problem completely? (And rebooting Band-in-a-Box without them being paired / connected).
Unfortunately, unpairing all my Bluetooth devices and rebooting didn't change anything.
I even tried disabling Bluetooth completely, which resulted in no noticeable changes, either.
One more thing: With the highest resolution I mentioned in my previous post, I managed to get a small visual delay even with Bluetooth audio.