That can happen to any bike. $10,000 to $400 job from WalMart. I had it happen on my very expensive Specialized. If you accidentally bang the derailleur it can bend the derailleur hanger and then when the chain is on the top of the cassette it hits a spoke and bam, its over. Lucky if you don’t wreck, let alone have any hope of saving the wheel. When I lube up my chain I take a second to look at the hanger from behind to see if somehow it has bent.