[object Object] on Tumblr while editing theme

Hello, i’ve just recently tried to make a tumblr page and whilst editing the theme i noticed i wasn’t able to view the preview and i was given a “[object Object]” on the top left where the preview window is.

I tried to see if it was the shield that was teasing me, but i disabled it and it still didn’t work.
I then opened firefox and tried to edit my theme there and the preview was there.

I have no idea what could cause this but i tried to google what object object meant and javascript popped up as one of the words, so i tried to disable the blocking for that aswell.

I don’t know if i’m posting the right place but i tried to see if someone had the same problems but i couldn’t find.

Best Wishes,