I have a S8 (bought new) for long time, and today, sundely Pattern lock stop working always says "Incorrect Patter Draw". I'm pretty sure I'm doing it correctly, as it is the same I have on other device. Consider this:
I do have account synced, but as I wrote initially, I can enter phone making using of fingerprint sensor., so I'm not blocked for the moment.
But, as soon Ill have to restart it (be that an update or a battert run out), I'l became locked, as it patten unlock at boot is configured! :( Besisdes, daily I'll have to pickup phone to swipe finger on sendor, and not directy on display as I used to do.
And the thing is... I cant change anything, as any change on this area will require a patern unlock first!!