Use the @torproject Tor Browser to access .onion sites, not Brave.
I just confirmed that yes, @brave browser's Tor mode appears to leak all the .onion addresses you visit to your DNS provider
If the @brave was used to open an .onion service - especially if it is self-hosted - it needs to be renewed ASAP.
TorV3 addresses are unguessable unless publicly shared.
If the public and private keys are deleted they will be recreated on Tor restart resulting in a new address.
Bitcoin Maston Instance