I've not noticed this on my iPhone, but have on my iPad, which, admittedly is old. My thought is this may happen because I have "Automatic App Updates" enabled and that there could be apps updating in the background. I've learned just to wait a while, and go back and check, and sure enough, it works just fine. It's very unnerving, and I do get anxious.
I don't know if this is the same issue you guys are having but wanted to share, just in case!
Last edited by Annie_i6s; 04-21-2016 at 12:23 PM.
Reason: Spelling!
04-21-2016 12:22 PM