Pretty significant bug:
Whatever happened in the last patch, it seems to have given US troops and vehicle gunners IR optics instead of NV optics or something
Here is several images of M113A2 gunners destroying BTR-60s through smoke with their M2s during a game, and during a test mission i made to prove the bug exists. You can see the tracer firecoming right through the smoke in all images. I have attached a test mission so you can test it yourself.
As it stands now. Covering with smoke while playing as Soviets is completely useless and pointless.