I did a little testing. I get the same error from any Chromium-based browser (tested Chrome, Edge, and Brave). But I DO NOT get the error when using Firefox. So it looks like the way Chromium is handling the page is tripping Avast/AVG.
Weeelll, I'm getting the same message from AVG. I know Avast bought AVG, but I would have thought the two would share resources, since they seem to share the same codebase. Or at least the same UI developers.