OS X 10.9.5, Chrome 56.0.2924.87
URL, probably irrelevant, was https://online-go.com/game/7999048.
Oh, I use the night theme. Maybe it was blank after all? Maybe that’s new information? You decide, I wouldn’t want to post it in the wrong place. Got all of the dev console text captured.
[Oh, one other thing. somehow I opened a forum page in the same window (actually, I think it might already have been open in a separate tab and I merely selected it) and it opened black . I copied out the URL for both pages and opened them in a new window and both opened as expected.]