Brave browser windows are blank

I set my preferences in Brave to open the previously-open windows each time I boot my Mac mini. Today when I started my mini, Brave opened, showing me my 50, or so, windows, each with several tabs, all of which are blank.

The URLs are there, all correct, but the graphic area below that is completely blank (white). I reloaded each page and after a quick wink of the reload icon, nothing else happened.

New pages or tabs I open and enter a URL behave normally; I can visit any website I wish. I can copy the URL from any of these blank pages and past it in a new Brave window and it will display the web page as expected. But these “frozen” web pages—as rendered in Brave—are dead. Likewise, all other network apps work normally (email client, other browsers, etc.).

I quit and restarted Brave as well as restarted the mini. No joy.

What’s going on? Anyone else experience this? How to overcome?

I’m aware of the diagnostic step of clearing Brave’s caches, but if the risk is killing the possibility of re-opening all these blank windows, I want to try all other options first.

Thanks,

Brave v. 1.29.79
macOS 11.4 Big Sur