I am not sure if this is Samsung specific, android, or just my S8.
Due to work related security I removed both the front and back cameras from my S8 a year or so ago.
Since I'm traveling to Japan for almost two months, I decided to install the cameras back. In doing so, i managed to fuck up my fingerprint sensor.
Now the interesting part is I use fingerprint or pin to unlock my phone, but ever since I messed the camera install my phone now unlocks without the need of a pin or fingerprint.
This is a huge flaw, as anyone with physical access to a phone can just disconnect the fingerprint scanner, switch on the phone and he wont need to know the pin to unlock it. Dont have another android device to try this on and confirm if it happens to others too.
Edit: false alarm, I am a complete idiot. I forgot that I recently set my phone to unlock when home. Has nothing to do with this, I should just delete this post. Idk