I do agree than the Xoxbox sound very different when sequenced externaly in general (didn’t tried with the OT yet tho so can’t tell if it’s really different).

I do most of the time use the onboard sequencer as I love it (running the original firmware here) but I for more “unstable funky” effect I like to sequence it from the Tracker / Live or other midi devices.

I made a video about the Xox with the Tracker a while back, od you recognize some of the weirdness your talking about maybe ?