No, balancer should come off with hand's, there should be a bolt holding the balancer to the crank. You did not say what vehicle or the eng that this happing on. This info might help answer youir question. If it come's off after the crank bolt has been removed, I would not be so surprised, but still yet, it should not just come off easly. I know some pontiac motor's would come off easy, and some old's motor's. Good luck, check, the key way, and take clalipers and measure the crank, and inside of the balancer. For ware.

No its not normal you might want to locate a replacement