I just encoutered this bug. I do not know what you mean exactly with steps to reproduse so I'll just write everything I notised:
I am using Firefoxx 46.0.1
It occured on the artwork page in the fresh section.
It seems that it is occuring more often the further you scroll down.
I although had the impression that it occured while loading single images in other tabs (wich is very slow). I am not shure abaut this point since it seemed to fit sometimes but it sometimes did not.
If you want to know anything else just ask. I will try to figure out what you need to know.
Customer support service by UserEcho