x0xb0x Sequencer Stopping Short in "Pattern (MIDI Sync)" Mode

[midiquestions]

My x0x is having a problem where it doesn't want to be synced up to an external MIDI clock. It will play note data fine in MIDI play mode, but when I send a start message to the internal sequencer in pattern mode, usually it just plays a note or two and then abruptly stops.

I've tried triggering it from a keyboard workstation, an MPC, and a computer, and it seems most likely to work as intended with the computer -- but still rarely. Most of the time, it stops about as soon as it starts, but I did have a stretch of a few hours recently where it worked perfectly.

Any idea what could be causing this? It has been doing this with both the standard firmware and now with a fresh install of SoKKOS 1.9.1 also.