rsync sends -C and -x options silently

[Anand Buddhdev]

Hello rsync developers and users,

I've just updated some of our CentOS servers from 7.4 to 7.5, and rsync
on these servers went from version 3.0.9 to 3.1.2.

This newer rsync version appears to be sending -C and -x options to the
server, even though they are not set on the client side. The client is
called like this:

rsync -rlptgo -qz --del --timeout=180 user at server /local/path

On the server, we have a wrapper script that parses all the options that
the client sends, with:

options=$(getopt -l server,sender,timeout: -o vnlogDtprzde.iLsf --
$SSH_ORIGINAL_COMMAND)

Now getopt keeps emitting errors that the -C and -x options are
unrecognised.

Is this a recent change in rsync to set these options even if the user
hasn't specified them?

Regards,
Anand