For me, it happens such:
20% of the time, fingerprint doesn't unlock the phone, but not unsuccessful reading, doesn't get the touch at all.
I need to finger swipe up on the screen and enter the code to unlock.
Even at home, when Smart Lock keeps phone unlocked, I need to swipe up to go past lock screen.
When it starts "not reading" I try each recognized finger and other fingers, the sensor just doesn't get any touch, the phone tends to turn screen off, due to inactivity.
Could you please fix this?
I have latest version, with May update.
The problem is there for 5 months, at least...