Daughters 5S has this issue. I looked at it yesterday, chose new fingerprint, and no response at all. Didn't do anything, didn't bring up a finger.
Phone is on iOS 10 but I gather its been like this for a while. Did a hard restart, no dice.
I don't recall seeing that as an issue although Im not on iOS 10 on my 6Plus and haven't read much about iOS 10 issues, although that doesnt appear to be the cause, given the time with the issue
Any ideas?