Could be worse, they could leave half way through when a specific boss doesn't drop loot.
Do you know how many Mythic AD runs died cause someone didn't get the trinket off Rezan, usually it was the tank who just wanted a quick que and shot at the trinket for his main dps spec, you knew when they ran straight to rezan what was about to happen.
You see it in LFR too, most recent the Raden fight for that trinket. Tanks would pull towards Ra'den with 20 ppl screaming "NO NO DO THAT LAST DO IT LAST REEEEEEEE"
My point is, it's nothing new it happens all over the game.