in miss case memcached module returned END instead of default 404 page body
the bug has been introduced in r2269

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index f567a43..ace467f 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -1441,11 +1441,6 @@
             return NGX_OK;
         }
 
-        if (status == NGX_HTTP_NOT_FOUND && u->conf->intercept_404) {
-            ngx_http_upstream_finalize_request(r, u, NGX_HTTP_NOT_FOUND);
-            return NGX_OK;
-        }
-
 #if (NGX_HTTP_CACHE)
 
         if (u->peer.tries == 0 && u->stale && (u->conf->use_stale & un->mask)) {
@@ -1471,6 +1466,13 @@
     ngx_http_err_page_t       *err_page;
     ngx_http_core_loc_conf_t  *clcf;
 
+    status = u->headers_in.status_n;
+
+    if (status == NGX_HTTP_NOT_FOUND && u->conf->intercept_404) {
+        ngx_http_upstream_finalize_request(r, u, NGX_HTTP_NOT_FOUND);
+        return NGX_OK;
+    }
+
     if (!u->conf->intercept_errors) {
         return NGX_DECLINED;
     }
@@ -1481,8 +1483,6 @@
         return NGX_DECLINED;
     }
 
-    status = u->headers_in.status_n;
-
     err_page = clcf->error_pages->elts;
     for (i = 0; i < clcf->error_pages->nelts; i++) {