I've had this problem for awhile now. I have ipad mini 6.1 and iPhone 4 Verizon 6.1. I have to tell each app update to download one at a time, or they fail. It's a pain. I have tried resets, and nothing helped. I am jailbroken but had this problem I want to say since 6.0, but I can't really remember its been that long.

Thanks