TC.
When we fit new pads to the rotor brake we have bed them in. This entails then brake being pulled on with rotors turning. Trust me. With rotors at max chat there would be no significant drop in NR. He would get a caption on his CAD 'ROTOR BRAKE'. And if the lever had been pulled...very unlikely..... It would be released again. The brake can not inadvertently come on in flight. Discount this idea. The brakes on the 135 are, to coin a phrase, a bag of crap. I wouldn't fit them to my bike.