I personally believe that they are intentionally forcing frame generation when the frames go below A certain level, to make the game look like it's performing better than it is. And they are hoping that no one will notice. The Steam overlay is the only thing that is letting us know.
I think I found the problem — it’s an option that comes enabled by default. You need to disable it:
Mouse & Keyboard > Control Setting > Uniform Infantry Aiming > OFF
As for the Frame Gen thing, it has nothing to do with it — it’s just a visual bug that happens when Reflex is enabled.
