Hi,
sure, how you know when you create a facebook app you need to create a hash for the android app. You must add a hash for every developer (if they use a different computer to develop). My mistake was that I used the same hash on every pc, (but it was ok with Android < 9, so I didn’t understand the error), instead of creating a hash for every pc that I use to develop (and pushing it on the facebook console) everything it’s ok. The different behaviour made sure that I didn’t understand the error.
I hope that it’s clear. I’m here for more details.
Nicola