I know nothing about Owner/Deowner or any IRCx stuff to be totally honest with you. I don't know any IRCx servers to test this on either bu try..
On me:*:Join:#: { set -u5 %owner.chan $chan }
On *:Owner:#: {
if (($opnick == $me) && (%owner.chan)) { mode $chan -q $me }
}
This sets a var for 5 seconds when you join a channel, deowner's you. If the var isn't set you'll stay an owner, 5 seconds should give it enough time to do it's thing.

-Andy