'find' function in openrc init script should be if [ -n "$(find /etc/ddclient -maxdepth 1 -name ddclient.conf -perm /0044)" ] ; then actually is if [ -n "$(find /etc/ddclient -maxdepth 1 -name ddclient.conf -perm +0044)" ] ; then which gives the error above.
find(1): -perm +mode This is no longer supported (and has been deprecated since 2005). Use -perm /mode instead.
This has already been fixed since 3.8.2+.