Recently, I had accumulated a little more than 1 BAT and had several logins/login sessions saved in various websites. When keeping multiple tabs open and closing the browser window, everything closes fine: no BAT is removed and no login sessions are ended. However, when I close out all the tabs in the Brave browser window individually instead of closing the browser window directly, my BAT disappears and all my login sessions are ended. Looking at the cookies and site data, when this happens, I can see that Brave has deleted the session cookies (hence logging me out of my accounts). The following settings are applicable in my browser:
Cookies: Blocked third-party cookies
Clear cookies and site data when you quit Brave: OFF
Also, sometimes when this happens, the BAT doesn’t reset to 0, but instead resets to an earlier value. For instance, yesterday I had about 1.670 BAT pending to be rewarded. When I closed all my tabs, it reset to 0.540 BAT (or close to it) and logged me out of all of my accounts.
Brave Version: 1.19.88 Chromium: 88.0.4324.96 (Official Build) (64-bit)