diff --git a/lib/server.js b/lib/server.js
index <HASH>..<HASH> 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -82,8 +82,12 @@ function handleResponse (opts, newReq, resp, response) {
             resp.writeHead(response.status, '', response.headers);
             resp.end(body);
         } else {
-            if (response.headers && response.headers['content-length']) {
-                opts.log('error/response/content-length', {req: newReq, res: response});
+            if (response.headers['content-length']) {
+                opts.log('warn/response/content-length', {
+                    req: newReq,
+                    res: response,
+                    reason: new Error('Invalid content-length')
+                });
                 delete response.headers['content-length'];
             }
             resp.writeHead(response.status, '', response.headers);
Include an Error instance in the log warning