External MIDI channel makes Playback stop?

[borducks]

Ok, I'm finally wading into sending MIDI clock to my MPK25, and with any luck, a Strymon Looper. I followed the basic setup, i.e. add external MIDI strip to patch, select send clock, start and stop, select my MPK and proper channel, set MPK clock to external.

The MPK got the tempo, although there's a noticeable lag, but anyway, that's not what's weird.

Now, with the external MIDI channel, the main play and stop controls are nearly unresponsive AND, any Playback instance set to start with Play Action stops after 1 measure. Not even an entire loop length. Doesn't matter which instance or which loop.

I checked things out with MIDI Monitor and didn't see any suspicious messages.

If I delete the external MIDI inst. channel, everything is ok again. Has anyone run into this?

-- edit -- Forgot to mention that after the Playback stops, I can restart it with it's assigned Play control and then it loops ok after about a measure of waiting. Snap To settings have no discernable effect on this.