Thanks for the info, it looks like a bug/feature in Boost when dealing with movie files from archive.org, a situation that probably doesn't happen that often. On the bright side, the movie stopped playing when I scrolled past it, so it isn't too bad. It looks like video ads work the same way, so it would only be particularly noticeable when ads aren't showing in Boost. It was an interesting experience, seeing all my favorite communities in another interface, I'll have to check out a couple others!