CV out broken on OG OPlab...?

After having used the OPLab successfully for several weeks, I powered it up today to discover that I can no longer control the pitch CV for my Pro-one from any midi source. I am using exactly the same setup as previously (Mode 0, mains powered, OP-1 or OP-Z as source). I have established that the Pro-One is still responding correctly to CV-In using another CV source, so it seems that the CV-out is the problem on the OP-Lab. I’m definitely looking to replace the OPLab soon, but I would certainly rather wait for a while if possible. Has anyone experienced this and fixed it? I’ve also tried re-uploading the firmware as it seems the closest thing to a system reset. And triggering notes on the Pro-One works fine too.