Hi,
This is NORMAL with the AMP2 and AMP3. There was an article online and I'll send it to you if I can refind it. It has something to do with the triggering mechanism and another pulse is needed. There's an adapter that will do this with a standard 12v trigger.
I use the trigger with my AMP3s and what I do with my Anthem AVM20 is that I've set zone 3 (which I'm not using) to power the amps on and off. I have to turn on zone three TWICE to turn it off, but that's the way the trigger is.
There's nothing wrong with your Proceed or with your Arcamm.