Mongrel instance halts, proxy error from Apache

Hello list,

I have started receiving Proxy Errors from Apache stating that it had
received invalid data from the server (mongrel). I then checked my
instances (2) with curl and one of them is not working (it seems to be
in an
infinite loop, it just hangs there and doesn’t output anything), the
instance is working fine… any ideas on what could be happening?

Thanks in advance,