Happens to me from time to time. No pattern that I can detect.
MacBook Air, Firefox.
I get random occurrences as well. It will almost always strip the bold formatting from the right side list if I answer a post them some back.
I'm still having problems with both the Escape & Fiberglass forums with intermittent half load hangs. The header shows, and the progress line stops about 1/2 way across. It takes 45 seconds to a minute or two for the page to finish loading. This is using the Safari browser on a Mac.
It has something to do with the coding on the sites, since I can immediately go to either of the Casita forums with no hangs.