If so, are these Bishops not acting in breach of their Vows?
I don't understand...
they don’t take a vow of obedience to the Pope unless they are Jesuits.
But they are supposed to follow the teachings of the church.
Bad bishops are not new. There was a time the Arian heresy, which believed Jesus was a demigod but not God, almost took over the church. St. Athanasius opposed them, and had to flee. The story goes that the soldiers were out to arrest him and he had to hide in a well...the moral being that if there is only one true Christian alive, even if he is in hiding, God can renew the church.
The Pope agrees with them and is probably the one organizing the meetings.