Don't use one on a 650 but curious....
I'm guessing you're either using a MP10 or MP700. Why do you need to shut it on/off while in cycle? Is the probe moving to an area where you're losing 'line of sight'? You should be able to just use the probe with the auto on/off setting and not worry about it. But, from the sounds of it, its like you've got another trigger somewhere. The probes can be triggered by M code or switch. Sounds like you've got one too many somewhere. Another thing, make sure your Tool Data page lists the probe for T80. (I'm assuming this was a factory install and not aftermarket)...
It's just a part..... cutter still goes round and round....