I’ve got a guy at office here working on a similar situation with a broken physics constraint. Trying to figure out if there’s a relation between his situation and yours.
If you don’t mind, can you maybe set up a keypress to attach tongue during runtime? What my coworker is seeing is that first time he applies an impulse to constrained object, it falls to ground. Every impulse after that works normally. Maybe if you can apply constraint after it falls to ground, it’ll work?