Any request by a client that does not contain a DNS name but an IP address and custom port in the HTTP request does not match any upstream rule except upstream http x.x.x.x:8080, even upstream http x.x.x.x:8080 "." or upstream http x.x.x.x:8080 "x.x.x.x/32" does not match. I tested it on 1.10.0-5+deb11u1