Normal
Yes they can pose a pretty serious threat to a molting or recently molted tarantula (or any invertebrate for that matter). This is why every book/hobbyist/just about every source out there will tell you to remove uneaten prey items and never to leave crickets or mealworms in with a tarantula that is molting. Crickets are omnivorous and will munch on a molting tarantula. When tarantulas molt they are extremely vulnerable and completely defenseless. Even for a while afterwards, their exoskeleton is still soft, as are their fangs, therefore they cannot use them to defend themselves. This is like very very basic stuff dude. I highly advise you do some more research on general tarantula care before buying more of them.