No idea what causes it. I know our server recently migrated us to their new data center. I'm probably going to end up having to shut the forum down for a day, and upgrade the OS, since it is end of life.
Yea, it's how the Google does ads now. When you scroll past one, it then anchors to top of screen in a drop down, on mobile.
I'm going to have to use a night some time in the coming weeks to upgrade our OS as we're end of life. I'm going to try to do a local build first to see if there will be major problems (minor problems will be ignored) with the forum software and the new packages. If there aren't, I'll then have to kill the site and do a live update. Our host doesn't allow us to download images, or restore from an image, so testing anything has to be done twice... or in production. For this one, I'm going to do it twice. So, if the site is down... it's because I'm working on it. I might give another notice, I might not. It's going to depend entirely on when I feel that I've got enough free time (and desire) in the evening to do the live update.