I've been having this as well for the last couple of weeks and it is extremely irritating. As far as I can tell, it is a problem with something that BING is doing, because I have the same problem on an 830 and a 625, irrespective of the WiFi network they are using (tried two) and the mobile network they are using (they are on different networks). I don't think that it is a rogue app as the two phones do not have any apps in common (except the standard load ones) and I doubt that it is a dodgy website because I very rarely use the browser on the 625.
Had a long conversation with Tech support this week and after soft-resetting the phone (and strangely, uninstalling the BA app) I appeared to have solved it... but a couple of days later the same problem is back. Done all the standard stuff of refusing cookies, deleting history and deleting offline storage etc... but nothing seems to shift it. the opera mini app is unaffected (though slow and clunky, so barely a replacement) so it must be something to do with the interface between bing search on 8.1 mobile and the current IE version.
And despite everyone saying that WP doesn't have malware / viruses, this seems a hell of a lot like one.
Anyone else having this problem? We need this fixed...