Can't navigate discussions.apple.com from Chrome

This is a follow up to https://discussions.apple.com/thread/251453234

I found this was occurring for me on MacOS on Chrome Version 84.0.4147.135 (Official Build) (64-bit). It was also affecting me to varying degrees on other sites, where sometimes I was getting a 404 even though other browsers worked fine. On Apple's discussion site I was getting a 422.

After comparing the requests from Chrome and the working browsers, I noticed that Chrome has moved forward with implementing the sec-ch-* strings, and that if I use an extension to prevent them from being sent (or set them to less strangely formatted strings), I can reach the discussion pages.

So it seems like a combination of some parsing of these new headers in Apple's servers, plus potentially strange data being sent by Chrome, that is causing the problem.