I had to look this up in the manual. You actually press Play to undo a record session? That doesn’t sound intuitive at all. IIRC, I have software that recognizes the Play button during record as a ‘okay, recording completed, stop recording and let me listen to the result’ kinda thing. I think it’s Logic.
Don’t we have another button available for Undo (and maybe a more general Undo)? That would also solve this problem, heh.
What about a combo like REC and the CLR mutator button? Something along those lines…