Hi!
According to the practical information I had from Policia Federal is:
They cancel the permanent residency if they know that the divorce was affirmed. (averbacao de divorcio).
I know a very close friend who got denied his entry to Brazil by federal police because he had already divorced, his status of permanent visa was already cancelled in the system of Policia Federal.
This person was entering to Brazil to continue his Postgraduate studies, as he had a full scholarship. He went to his home country just to visit the family. He did not know that his Permanent RNE was cancelled, while he was handling RNE card in his hand. At immigration, Policia Federal collected his RNE and denied the entry.
The Policia federal came to know that he was a legitimate student, they denied his entry and asked him to come to Brazil based on a student visa to study. This person showed me his entry refusal letter as well as Permanent RNE cancellation letter issued by Police.
Now, I know that Permanent visa can be cancelled upon registered divorce. If you are already in Brazil, don't go anywhere without regularizing your status, otherwise, you can get in trouble.
I hope this helps you.
Thanks