Put a UAD compressor in a return track for parallel compression -->> it starts flanging.
Closed the set, Changed the buffer from 64 to 512 -->> now it's echoing.
Tried it with Ableton devices. Same thing.
With only ONE track playing and delay compensation enabled.
Tried it with Simpler, all seemed OK.
Tried it again with Drumatic, same thing (slapback delay)
Click on Freeze trak DELAY WENT AWAY (!!!)
Clicked "Cancel" now it plays as it should...