The CY2304NZ has a active high OE. When it is high the outputs will be enabled and follow the BUF_IN input. When OE is low the outputs will be low as the datasheet shows.
Thanks and Regards,
Actually I've confirmed elsewhere that the outputs are -not- tristated when OE goes low. The outputs just go to a logic low state when OE is low.
This is not how I would normally expect the OE pin to operate. Nevertheless that's how it works with this part.