I have had the same issue in DOS 1 and no, this is NOT the player's fault.
The player was required to select the hit box of the mob and since they don't stand still but always have some animation it would occur sometimes you would click on them at the moment they start their animation and bam your character moves instead.
This is infuriating!
In the end I was always zooming in as much as I could and wait for the stupid mob to finish his random animation to attack.
There was also a bug with some knockdown mob (Half body zombies I think) and they were sometimes flashing making the cursor flash for a brief period making your click be a move instead of an attack.
No they were not players error they were simply a flawed mechanic and a bug.
Although I have not encountered this issue in DOS 2. I think you can just target their round base to make sure your order gets were it should. So all is good in the EA at least.
But a move lock could be fine.
I guess if you press CTRL and click you kinda have the same but I am not sure if your attack will hit the ground instead of the NPC.