Ok. I see the problem but I’m not sure I can help. I’m guessing that both physics and animation movement compound to create this behavior. Unfortunately I haven’t played with ragdolls that much. I can suggest you try disable physics for the hand (if you haven’t) with SetAllBodiesBelowSimulatePhysics or set very small physics blend SetAllBodiesBelowPhysicsBlendWeight.
Check this post: How to do a partial ragdoll? - #2 by Black_Phoenyx The OP wants exactly the opposite but you might find it useful.