Parts turn off when playhead loops back to the start in Reaper

[Travesty]

Ok, I don't know why, but I started from scratch and set it up again, and now it works fine when looping.

"If The NDLR gets two “stop” msgs in a row it will stop AND “disarm” all the parts. "

I think this is the reason, if it happens again I'll try and get a midi capture