Hmmm. Not sure, but a few points in case they help
- The mesh seems fine...
- The attachment origin for the shoulder I was expecting to be green, but I don’t think that is the problem. The arms seem to move fine.
- My main suspicion is you have added extra dragger behaviors per arm and have multiple draggers armed at the same time. You can have one dragger (e.g. on the root of the puppet, the default) and manage all draggers in the puppet. The behavior guesses the closest dragger based on where you start the mouse click and drag from. Because you have added a behavior per arm, those draggers will *only* find the dragger on the arm they are attached to. So having all 3 draggers active at the same time will cause your problem. (See how there are red dots against the root Dragger, the [LArm] Dragger, and the [RArm] Dragger? I think that is the problem.)
So solutions are either
(1) Remove the draggers on the arms - just using the one on the root of the puppet is fine, or
(2) Make sure you don’t arm all the draggers at the same time.
Sometimes I do use multiple draggers. But I tend to do so more when I want do record one drag for the hand, and a second drag for the elbow later where I want to see the first drag. But if using the IK-arm behavior now, I would not bother. Just have a single dragger behavior. You instead record values for the elbow strength if you want to change how the arm moves in the middle of a scene.