This trial is totally bugged in RTQ on PS4.
#1 It takes way too long to kill the dragon. It's HAMSTER, it should not take 30 minutes for 6 DPSes to kill a dragon.
#2 50% of the time when you finally get to the end and he is dead (health bar appears to be zero) he vanishes and you are stuck in limbo, unable to finish. So you have to Abandon and then go back into the RTQ queue.
This needs to be fixed or take this trial out of RTQ.