I've been getting spam type page redirects in the B8 A4 forum as well. It's on an Apple laptop running Safari. When it happens, it's usually along the lines of "your computer may be infected, download this" or "your flash player is out of date, click here to update." When's it happened, I've not been able to use the "back" button to return to the previous page and just have to close the tab altogether.

It's been happening for the last several months, but I haven't gotten screenshots or link addresses from when it happens. Next time it does, I'll try to scrape up more details. I only browse on my computer so don't know if I have the same issue on my phone browser.