Comment 3 for bug 1641238

Reverse proxy of 100-continue aware backend, sends 100 continue even when backend does not. This causes a client to think it should write a request body, while the backend may still respond with a 400 and not read the request body. mod_proxy_http then responds with 502 as a result of AH01097: pass request body failed

The backend is doing the right thing: it did not send a 100 continue so it should not be required to read a request body, regardless of transfer encoding or content-length.

Expected:

mod_proxy_http reverse proxy should not send 100-continue to a client unless the backend does.