Don't call it pilot error,call it management error.
Any pilot flying with these engines should know that you should keep your fingers well clear of the triggers whenever in the air. It is clearly written in the manuals about selection of power levers below flight idle in flight being prohibited.
There have been several cases of accidents happening for similar reasons and there is usually a common theme. The pilot was higher or faster than he wanted to be and somehow the two actions of pulling those triggers and then moving the power levers aft happened.
One has to wonder how much of a random coincidence it is that almost every time if not every time the triggers have been activated flowed by power lever movement aft beyond flight idle in the air leading to an accident, it just happened to be when the pilot really wanted to go down or slow down.