Overloading a getter from a super class and then delegating to that parent class requires using the actual method and not the property accessor when using static compilation in groovy 2.4.0. This is something we do to add hibernate validators to a subclass of generated code. Not using static compilation on the subclass or switching to groovy 2.3.x resolves the issue.
>>> 2.4.0 output
>>> 2.3.6 output