i found a fix. open the download page (ctrl J) … click search and put a single period . as the search query, then search, it will then show the downloads. This seems to refresh the download page list so you can see the files.
Resizing works, @Mattches, and is more convenient than opening and closing Developer Tools, which is what I was doing once I noticed this in Brave Nightly this afternoon (Version 0.70.36 Chromium: 76.0.3809.87 (Official Build) nightly (64-bit) Win10 Home 1903, also previous version of Brave Nightly). The same behavior was occurring on macOS 10.14.5 Brave Nightly Version 0.70.34 Chromium: 76.0.3809.87 (Official Build) nightly (64-bit), as well as in Nightly 0.70.36 for Mac to which I just updated.