My wife and I both are having the same issues with both our phones! We have updated the iOS restarted, reset. Their is something seriously wrong with either the iOS or this hardware. This phone has disgraced APPLES reputation as being solid glitcheless phones.
This phone reminds me of the Windows Mobile phone with all it glitches.
I Put down a lot on notes in my contacts, I absolutely hate that you search for information but when you tap to type it jumps you all the way back to the top of your list. This phone bogs down and locks up. takes off on it's own and does what it wants.
Programming needs serious help. I pay a premium for these phone because I expect a solid phone.
What is Apple going to do to fix this. These issues are not isolated.