Logsout when tab is closed instead of window

Yes. It looks like the same issue as:

and

Try going to settings: Privacy & Security >> Cookies and Other Site Data >> Clear Cookies & Site Data and turn this setting off.

Reload Brave

Go back to setting: Privacy & Security >> Cookies and Other Site Data >>Clear browsing data>> on exit >> and select cookies and other site data.

Closing the tab should not now clear the cookies (Well it didn’t for me!) but reloading Brave did.