I got something that was weird yesterday; I wish I'd taken a screen shot. It was a quest that was completely invisible ... the quest was there, you can tell by the fact that it had a thin frame around it, and you could hover over it and see what it was, but there was no picture whatsoever ... you could see through to the landscape underneath. I completed the quest and got a green checkmark, but I couldn't collect it ... it wouldn't let me, until I refreshed and came back in. Then it was there with the picture.