Shotgun Delay?

[Terran]

The last version ran fine. But it seems with 2.5 whenever myself or anybody in the map near me (including bots) shoots the shotgun the game like "jumps" in sync with the explosion sound. Originally i thought i was supposed to be recoil, but it happens TO ME when other people fire too. It's like the FPS is dropping really badly for a sec then going back each time.

This happens on LOW and MEDIUM.

[Terran]

It appears to be caused by the rendering of weapons flash, i see it happening with other weapons too, and when they're in rendering range.