Rare problem
I've been with EE about a year (on T-mobile for about 7 years prior to that) and this is the first problem there's been that has affected me.
No pop-ups or authentication messages for me though (Galaxy Note 3) just not data for an hour or 2. Wasn't a big deal for me though as I'm at work, so I was just briefly without data as I walked between buildings, WiFi everywhere else.