Hmmm, some things to consider:
If you came from 8 LE(or M-Powered) which had no delay compensation, did you actually nudge things in the original session(which puts them out of time with ADC working now)?
Do you have any AUX sends that have no destination track? This can cause bogus delay compensation. With this in mind, set your view to show Delay Compensation(MIX window) and look for numbers that don't make sense(might help track down a cause).
Save a copy of the session(WITH audio) and open the copy. Delete all the buses and sends and rebuild(if this doesn't help, at least you didn't mess up the original)
