Many balancers have slipped and the engines are still running.
How about the outer ring on the balancer is neutal balanced with a mark for the timing. So if it slips it changes the timing mark position not the balance.
Only if you are lucky. Once the outer ring is unbounded from the inner it's junk and doesn't work.
That's why I NEVER EVER buy a damper like that. They start to lose effectiveness almost immediately as the rubber changes durometer and starts to break down.
It's a crank breaker. I hope the OP is lucky. Some guys run junk and get away with it.