I don't think it's a full restart, just Springboard crashing and restarting. After a real restart, I think the phone is supposed to required a PIN, instead of a

I don't think it's a full restart, just Springboard crashing and restarting. After a real restart, I think the phone is supposed to required a PIN, instead of allowing the fingerprint sensor to unlock it. But when this happens to me, the fingerprint is sufficient to unlock.