I wonder if it is possible to accidentally grab the trim switch whilst thinking you are hitting (and holding) AP DISC..
Based on my Cirrus time, yes this is absolutely a possibility, as they are the same button, BUT... you clearly know that you have disconnected the autopilot because a very loud series of beeps comes through your headset, probably 8? from memory, but if you press and hold the AP disconnect, you only get 1 beep. It would be possible to have several goes at pressing the button whilst pushing back the trim, however you'd simply push it forward afterwards.
It would be really good to know how experienced the pilot was in this aircraft type so we could better understand what might have happened.
