Was about to post something.
I'm not sure if it's the "screen protector" they shipped with it that can be causing my little issues, but I'm not a fan of the reader. A few mins ago, I didn't even touch the glass, my thumb was about half inch from the glass, I felt the phone vibrate multiple times then I get an error. It said that I entered a mismatched print 5 times and now have to enter a code. My thumb never touched the glass, and was at least half inch over it, hovering the phone.
Aside from that, the touches are not consistent. Sometimes I have to press hard, sometimes soft, sometimes diff parts of my thumbs.
I've deleted my prints and redid them just to make sure I had good prints.
If this annoys me much longer, then I'll pull the screen protector off an see if it makes any diff. I do think it's the culprit tho. I never been a fan of using them. Never scratched any of my phones and I put them in/out my back pocket all the time.