Sounds like it all worked out.
P.S. It also seems like the thread title could be updated too since it seems that iOS 8.1.1 (or even just iOS 8 or iOS in general) didn't have much to do with any of it.
According to one of Apple patents, they can trigger with software faulty or not working properly hardware... Like there was issue which appeared only after iOS 7 update when a lot of iPhone 5 users started to get random shutdowns. I think it is possible