I'm periodically getting the following error pop up on GZ forum pages.

Failed to load content css: https://cdn.tinymce.com/4/skins/lightgray/content.min.css

It shows up in a pinkish highlighted box floating over the pages. Has persisted through various versions of OS X Firefox. It might show up once in every 20ish pages viewed - only possible pattern I can see is it appears to be far more common if I open multiple tabs of GZ with different threads in each. Done the usual cache clear etc. Adblock installed but whitelisted for GZ (shows no items blocked).

I see that @Rikkitic had the same error in this thread but that seemed to be an Opera issue at the time.

Anyone else seeing this at all?