KNOWN_BUGS: transfer-encoding: chunked in HTTP/2

Closes #662

docs/KNOWN_BUGS

@@ -22,6 +22,7 @@ problems may have been fixed or changed somewhat since this was written!
  1.8 DNS timing is wrong for HTTP redirects
  1.9 HTTP/2 frames while in the connection pool kill reuse
  1.10 Strips trailing dot from host name
+ 1.11 transfer-encoding: chunked in HTTP/2
 
  2. TLS
  2.1 Hangs with PolarSSL
@@ -193,6 +194,13 @@ problems may have been fixed or changed somewhat since this was written!
 
  See https://github.com/curl/curl/issues/716 for the discussion.
 
+1.11 transfer-encoding: chunked in HTTP/2
+
+ For HTTP/1, when -H transfer-encoding:chunked option is given, curl encodes
+ the request using chunked encoding. But when HTTP/2 is being used, the
+ command wrongly sends a request with both content-length and
+ transfer-encoding: chunked headers being set (and the request body is not
+ chunked-encoded). See https://github.com/curl/curl/issues/662
 
 2. TLS