Which version of Brave are you presently using (see brave://version/), do you happen to also be using Brave Sync (via brave://sync/) as well? If you’re using Sync, do you see any configurations that aren’t as you’d expect when visiting brave://sync/?
When the Bookmarks are not visible via the menu, are they still shown when you visit the internals bookmarks page at brave://bookmarks/? If not, what is the process you have found to bring them back? Simply restarting the browser?
@Henri9009 Sorry, could you clarify that last message for me. The bookmarks are note visible from the menu, but are visible from the bookmarks page? And restarting the browser will at times resolve the issue, making bookmarks visible from both locations?