I have experienced recently as well, I think. My mobile account was connected to the same wallet as my desktop account, recently my mobile account was disconnected without any prompt from me. I have tried connecting the same wallet multiple times by entering my account seed phrase, but after getting a message confirming the new connection, it reverts back to a disconnected state. I tried creating a new brave wallet to see if that would work, but I get the same result.
Not getting much in the way of answers regarding my problem. Is there any other place I can ask for technical help? Maybe a live chat or something similar.