Windows 10 / Chrome: HTTP browser request to IP address differs from same request to hostname

Apparently under some circumstances, the Windows client would try to get the address of HPMICRO1.... from 8.8.8.8

This isn't a Windows bug, this is by design. You configured the Windows DNS client with a primary and a secondary DNS server. The primary server failed to respond so the Windows DNS client queried the secondary server. That's the perfectly desired behavior. Would you rather it fail on querying the primary and not query the secondary? Are you implying that other DNS clients don't behave the same? That they'll only query a single DNS server? You seem to be trying to make this a "Windows is at fault" screed when in fact, the Windows DNS client is behaving exactly as it was designed to. If the primary server doesn't respond, then try the secondary, then the tertiary, etc. This isn't a client issue, it's a server issue. Check your DNS server, that's where the problem lies.

I'm not sure what caused Windows to do that.

I've given you a link to the article that explains the behavior. It isn't a mystery. It's working as it was designed to, the same way every other DNS client resolver is designed for the same behavior. Query the primary, no response, query the secondary, and so on, and so on.