HrblsHave you checked that screenshot isn't bound to a common key? I had similar stutters a few months back because my VOIP key+tab was bound to take a steam screenshot.
Screenshot it's bound to F12 so, i never press that.
Yesterday i played like 3 whole maps of 30 minutes and it didn't freezes.
For now, it seems that removing the particle effect or the soldier's arm fix worked.
I will update this thread if it happens again.