Maybe there’s a MIDI Note filter engaged or MIDI channels are not matched between Ableton and Biscuit (clock messages are sent on all channels).
Go to Biscuit mode (4 + 5 + BRAIN) and check the MIDI filters, specially nr 6, Receive note filter.
Should not flash.
You can also set the right MIDI channel.
Go back to Der OTO mode and check if it’s OK now.