A recent update (April 1) to my 8.1 seems to have broken the fingerprint reading functionality. It worked flawlessly before, and now it fails about 75% of the time. I removed all fingerprints and tried to add new ones. When I do, about 75% of the time it is telling me that the lens is dirty and that I should clean it. I cleaned the lens with no change. I have had the phone for a number of months and have never had any issue or message saying to clean the fingerprint reading lens. Any one have any idea how to fix it?