I have just noticed one odd thing. Usually when I try to add the fingerprint, it seems to scan and vibrate OK and then tells me it failed. However on a couple of occasions it said it would try again in one hour. I'm just curious why it should be time dependent at all - as if it's trying to transmit data unsuccessfully - you can guess what I am thinking - I'm probably just being paranoid.
I did a dirty re flash by the way and that didn't help. Don't have the time or energy at the moment to do a reset/wipe.