RELEASED: IWBUMS Build 39.67.3
Available on Steam beta branch 'iwillbackupmysave'
New Features:
Vehicles
Er... lots of other stuff to numerous to recall. We'll look into an overview of added features at a later date.
Post your bugs over here!
I think something goes wrong with the physics "interpolation" that causes this. Try setting the PhysicsDelayServer option to zero and reconnecting and see if it fixes it. (Assuming you are running the server.)