fix case when two directives
    proxy_pass   http://backend;
    proxy_pass   https://backend;
both use one port - 80 or 443, that was defined first.

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 376b85f..bc45674 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -3209,6 +3209,12 @@
             continue;
         }
 
+        if (uscfp[i]->default_port && u->default_port
+            && uscfp[i]->default_port != u->default_port)
+        {
+            continue;
+        }
+
         return uscfp[i];
     }