To anyone reading this, i have no clue what changed, i have tripled checked before posting this, as I had done the last 5 days every day. I just tested in Safari (hadn't tested there before, only the other two major browsers), and got presented with the native SignIn dialog with TouchID, which immediately worked. Went back to the other browsers to check again, and the tabs i had left opened on the "invalid_request" error from 5min before posting this, magically worked now. I have not changed a thing in my config, except maybe saving again what was already there. As i had done every day since last friday. I am glad the issue now seems resolved, but I would still consider that this propagation issue be fixed. On other OAuth providers it took less than a minute for this configuration to be updated and work. Configure OAuth shouldn't feel so obscure.