I used to own a brand now fairphone 3 until this moring.
Friday evening I was using my fairphone when i got stuck at the lock screen.
I could not unlock the phone even after a normal restart, switching it on and off and waiting multiple times.
Other times it would show multiple numbers when trying to enter the lockscreen code.
This Saturday I went to the shop and and on my way to there it would work normal again.
I wanted to make a backup and then hand it in for repair.
For some reason it would one moment work and other moment it was stuck at the lock screen.
At home I found out that I was still within the bring-back-period of the fairphone 3 to the shop so I went in and asked a refund.