IPhone 6S battery life stuck
I've noticed a couple of times on my iPhone 6s, that the battery life will be stuck on a certain number. I'll be using my phone, but the battery life won't show it having drained at all, or I'll be charging it and the battery life won't show any improvement. If I turn my phone off and then back on, it will usually update to the correct battery percentage.
Is this a common problem with the new iPhone? What can I do to fix it permanently?
iPhone 6s, iOS 9.0.1