the same thing happened to me then I realized that it depended on Nova Launcher when I used his screen locker, now i don't use it anymore and everytihng is ok!!Is the silly security feature in Oreo where randomly a pin is required instead of biometrics housed in the rom or in the kernel?
I'm sure that is a silly question but I was just wondering if I should try TGP or something just to see if I can get rid of that.. It's really annoying and also effects smart lock etc
S9 plus - Soldier rom