Periodic Timeout? Re: Happened to me.
I've had to re-log-in a fair few times on my mobile - I had thought it was due to me logging in to gmail on the PC without closing the app on the phone (yes, old habits die hard), or because it had magically turned itself off* and at other times I thought it was due to my insistence on disabling lots of services and overdoing it.
First time got a WTF and clear-all and confirmation of what was demanding the re-log-in, now the WTF is just FFS instead. But lots of other people at the same time? Definitely something hinky going on, the usual cause is the government installing another black box somewhere.
* by cleverly using up the battery by doing Unknown Things and switching H/H+ every few seconds because that's really important while the phone is just sitting there, seems to depend on what had been running, even if all cached apps are cleared, obviously my mind was harder to control at those times...