My overlay repo adds a lang/rakudo port. This port is expired in the main repo over which I'm applying the overlay. The MOVED setting applies. There does not appear to be any provision for overriding the MOVED expiration in the main repo from the overlay, meaning that one must modify the main repo or use a duplicate port name to add the port.
Proposed patch here: https://github.com/freebsd/poudriere/pull/772