Current implementation rejects requests with Transfer-Encoding: chunked and Content-Length headers with HPE_UNEXPECTED_CONTENT_LENGTH.
https://github.com/nodejs/http-parser/blob/master/http_parser.c#L1804-L1815

But per https://tools.ietf.org/html/rfc7230#section-3.3.3 that's a valid http request, Content-Length must be ignored:

       If a message is received with both a Transfer-Encoding and a
       Content-Length header field, the Transfer-Encoding overrides the
       Content-Length. 

llhttp parser has the correct behavior: https://github.com/nodejs/llhttp/blob/master/src/native/http.c#L50