@EA_Illium it's not related to enemies still alive in area's, i got it at random everywhere in ME1LE and ME2LE, although less in 2.
I also got the same problem teporarily with not being able to fire my gun for a short while. Feels like the same kind of bug actually as the stuck direction/ not being able to aim bug.
It's randomly messing up the mouse controls for a short while, sometimes it's movement, sometimes it's unable to fire.
If it's movement, i can still fire, and vice versa.
The game seems to lose control of a part of the mouse.
But, it happens with the keyboard too, it also sometimes get unresponsive for like 20 seconds and then start working again.
The older versions of Mass Effect 1, 2 and 3 never had any bug with me, the Legendary Edition is riddled with bugs for me, crashes, control freezes, suddenly temporarily vanishing/teleporting NPC's.
It's obvious that it has something to do with porting the old code to the newer Unreal engine, probably some deprecated script commands that need to be corrected. Tell the devs to search for it in the controllers code.