Things I've tried that do not help (except for the duration of the overriding animation):
-Dropping what's in hands
-Putting something else in hands
-Switching melee weapon
-Sprinting
-Vaulting/Jumping
-Pressing Spacebar to exit combat-mode (lowering fists)
Things that help indefinitely... sort-of (bug returns when I'm standing again)
-Crouching (moving or still)
-Prone (moving or still)
-Swimming (moving or treading water)
Things I've not yet tried
-How a loaded gun interacts
-How an unloaded gun interacts