found a cause for a FREEZE case...
i found that when you have, say, track 1 set to receive MIDI from MIDI channel 1 and have AUTO CHANNEL set to 1, that any external MIDI message coming in on channel 1 will cause the DT to crash.
i was changing AUTO CHANNEL to 16 while tapping on a MIDI keyboard assigned to DT. it crashed. so i restarted and saw it hung on AUTO CHANNEL 1. so i left AUTO CHANNEL on 1, track 1 still set to MIDI channel 1. pressed one note on the keyboard and it crashed the DT again. repeatable.
can reproduce [repeatable ha ha ha, oh man]