Wild guess:
Click on Brave Shields icon in the address bar
One or more of those settings, probably you need to adjust. Could be the cookies are blocked, and you need to adjust that to “Cross-site cookies blocked” or maybe “All cookies allowed” . . .
IOW, test the possibilities of the various switches.
And . . .
Brave Support will need more info:
[They request] Please adhere to the guidelines to the best of your ability, and use the Template shown in the Reply Editor. [No quotes, in the following links - copy and paste the link into new browser windows:]
How to submit a Bug Report:
“https://support.brave.com/hc/en-us/articles/360018228951”
The Brave Community webpages use a Categories and Tags - topic organization system - that assist Brave Support and Community members.
Sounds like, for your concerns / issues, you might select:
Browser Support > etc.