Google may have a bug with the URL inspection tool in Google Search Console specific to websites on HTTP/2. The tool shows a malformed response when it is run on the HTTP/2 server.

The individual who posted this on Reddit said “I’m curious if anyone else is seeing this…. When I look at the Crawled Page data in GSC it’s showing the HTTP Response as “Malformed response”. When I run a live test it checks with HTTP/1.1 which is fine.”

Gary Illyes of Google responded “Yeah I’m looking into this. sorry. Meaning to say this is likely a bug in SC.”

Here is a screen shot (click to enlarge):

I asked Gary for an update about this but there was not one to be given:

Forum discussion at Reddit.