Hello!
I found some bug in android Oreo.
It`s about skipping phone locking.
I meet this problem after i forgot my graphic key.
As usual u have endless number of attempts for unlocking phone. 
But if phone owner lock phone from google.com/android/find - u cant unlock it.
BUT if phone owner whrite his extranumber for calling for return - u can exploit it.
After u start calling on "return-number", immediately reject a call. 
After that u can make 1 more attempt for unlocking phone.
U can repeat it as much as u want.

Sorry foe my not perfect english.
I hope you understand all, but if you dont - pls ask me, i chat back in shortest time!