I'm not sure how this is possible. It had been a week since I last logged in to my Graphene phone since it is not my main phone. It unexpectedly buzzed several times. I picked it up and it showed a white screen but not the login screen. I tried to figure out the screen but it reset. It showed the recovery mode menu then "You are loading a different operating system," etc. After it restarted I noticed the battery was 1% and the charging cable was not plugged in all the way. I charged it and then tried to login. I couldn't login.
I am very certain I know my PIN but I wrote down and tried all possible digit permutations of it in case my memory reversed some digits. I have tried about 40 PINs and I have to wait 60 seconds between each try. But I am still certain I know my original PIN. I have been using the same PIN for months.