I’m using
Version 1.9.76 Chromium: 81.0.4044.138 (Official Build) (64-bit)](https://brave.com/latest/)
and it will not remove the Top Site. There are many posts on this. If you close and reopen it, the Top Sites will pop right back up. Even pinning/unpinning doesn’t help.
I encountered the same issue. Even after deleting browsing data (for “All Time”, advanced, with every box checked) the “Top Sites” persist. This seems like a disqualifying fail for a “Privacy Browser” in that a user might expect to have cleaned everything up but some of their activities can still be found.