I have had a lot of trouble with recording to and playing back a buffer at the same time.
When the OT firmware was still in beta you could manipulate the Pitch and Rate parameters for a Flex machine while playing a buffer that was being recorded to but it resulted in occasional noise bursts.
Now it appears that if you change these parameters while playing a buffer to which you are also recording, you get silence.
I haven’t tried to reproduce your steps (I don’t have the time, I’m afraid) but I would not be surprised if you are having issues with that use case.