I first noticed these symptoms last week, and had this in the back of my mind to track down. I deployed our Meteor app to an internal server last week, and started having problems with Firefox. Firefox is still my default browser (yes, I’ve heard ALL THE THINGS about Chrome, but I haven’t changed), so it was a little sad to discover that my app didn’t work. In particular, my first page ended up being completely blank because a JavaScript exception was being thrown and no rendering was taking place.
Looking into the JavaScript log, I found this error:
SecurityError? The operation is insecure? Wuh?