Yesterday, while I was out killing dragons for the event, some of the dragons would attempt to fly away (like they normally do during a fight) and get their tail stuck in the ground. While they were stuck flying their health would still go down to 0 but they would not die. There was an instance where 2 of these glitched-out dragons would not go to 0 HP while glitched (giving no credit for the slay dragons daily and no rewards for killing them) and would just stay stuck while flying until some time went by and they reset. I would say this glitch occurred 5 or more times yesterday.