Im using keyboard+mouse to play, but i have an Xbox360 controller plugged in.
If i fire a flare the gamepad starts vibrating violently, and i doesnt stop untill i quit the mission.

The problem is easy to replicate, happens every time.

If you cant replicate it i will be more than happy to make a video of the issue.
i hope you will be able to fix this, as its a bit distracting when conducting a heli raid on a enemy base and the Xbox360 controller is vibrating and making the worst noise ever when the controller sits on a wooden computer desk. _)