Poor software implementation that is all. It seems to have a mind of its own. Some kind of personality. Sometimes it works registering fingerprints with moisturiser, but 80% of the time it does not. Sometimes it works buy putting your finger of a wet cloth before each scan of the finger - but sometimes this does not help either. Sometime if you let it aside for a while and when you try again after 20 or 30 minutes it registers very quickly your fingerprint.
Another annoying thing is that from time time it doesn't recognise one of the fingerprints. Don't bother to try to registrate again that fingerprint - it will not work and it will annoy you to hell. Just leave it for half an hour and after that like a miracle it reads again your fingerprint.
I made 3 updates and nothing seems to be changed with this problem. There are times that it works quickly and time that it does not want to work no matter what you do. You can try with or without the temperred glass. with wet hands, with moisturiser. it does not want to work properly and consistently.
So after 3 updates and after all the experience that I detailed above I can assume that it is a poor software implementation.
I've tested the same tehnology on the chinese companies like Xiaomi and Huawei and they have faster unlocking and always reads your fingerprints. Besides that, on the chinese phones it works by reading the tip or the sides of your fingerprint - something that samsung does not want to work. The position of the scanner on samsung is too low and when you want hold the phone with one hand and want to unlock it with your tumb you have to make some streching to allow samsung poor software to read the middle of your tumb because it won't unlock by reading the edge of your tumb or the tip of your tumb. Others can, samsung can not do that or not all the time only 10 - 20% of the time.
So if the chinese can do it please cut the cr*p samsung and work on the software and don't full us with things like don't use tempered glass, don't use plastic protectors ... your software tells us to not use fingerprints if we don't want to get annoyed.
