It seems something is triggered. As tnussb said may be MIDI or samples on a track. Could be muted or cued. Check if “cue mutes track” is active and these tracks are cued.
Further to my previous posts, I’m happy to report it was just user confusion on my part which led me down a crazy path
All is good with my OT.
For some reason I had never noticed before (despite using daily for 2 years…) that P Locking the trigs will make them blink.
So when I’d opened an old project on which every trig was blinking I thought that this was an error, and then all my other projects were showing the same ‘problem’
Then whilst messing around with it to see what the problem was, I must have clicked of grid record. Hence why I could see the trigs going on and off when the sequencer was playing.