While doing the main story quests for TWW, after I turn in one quest I am unable to accept the next quest unless I use the /reload ui command.
I am using no add-ons whatsoever.
I’ve found that it will usually bug out and have the dialog opened but invisible… I usually just run out of range of the npc (5-10 yds or so) and come back to finish accepting or completing quests. never thought to reloadui for it.
I have had it happen at least half the time as well on another toon. I just move a way a little as well (enough the NPC ‘ends’ the conversation) and then click on them again to continue. Works every time as a ‘fix’ for me.