Never heard of anything like that -- certainly sounds like a hardware issue, not an Evo issue, but if it doesn't happen in all missions then I'm really not sure. Nothing in the Evo scripts modify movement, so you've got a really odd issue... do you have controls mapped in odd way, or something, perhaps?

I get that same problem if I play ArmA2 with any controller plugged in. X-45, or a simple joystick, or my Logitech MOMO wheel.

That is a controller issue that is intermittent at best. I get it on occasion and usually just have to unplug my X-52 from the USB and plug it back in (after exiting ARMA). Sometimes I notice that if a vehicle is parked with it's wheels turned that I get that problem as well.

I will check my X-52.