I had that happen to me in a Mooney once. Scary stuff. The only related problem I've had is that the power levers can be very sticky on one of our airplanes, sometimes with just a little movement and the torque jumps up or down 200 ft/lbs.
The first time it happened I couldn’t figure out why. After the second time, the IA told me the dirt/grime in the power quadrant can result in tension at the idle position and almost none at the top end. It’s usually the left side because the cable is shorter. This means the spring on the push rod at the other end has less resistance.
Here’s the thing: no afx because the engine is still working and the micro switch isn’t satisfied. So you have flat plate drag hanging out there at precisely the wrong time—it snapped back when the pilot moves his/her right hand from the PL to the gear handle. Do they complete the procedure, put the right hand on the yoke, or better yet, verify Power Maximum Allowable? When the investigators get there, there is no obvious malfunction in the engine and they have to come up with possible answers like water contamination.
Read up on the crashes at TUS, LGB, ICT, and YMEN for starters. All went to the left. No survivors.