I'll go on record without the problem, using AT&T and no iCloud use except for Find My iPhone.
I'll second. No iCloud except Find My Phone. Seems far greater with Verizon.
Maybe a conspiracy between Verizon and Samsung? Remember, "How to sell against the iPhone"? Nah.
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AT&T, with the number of issues being reported and the fact that this happened on my iphone 4s when I upgraded to ios 6 when the GM came out I think that it is an iOS issue in the handling of icloud backups and wifi when screen is locked.
If anybody has icloud backups turned off and is seeing this please post because so far this is the leading theory at least for myself and a few others
Seriously. You're onto something. Check iCloud people.