The Dutch (an AI empire) built the Hanging Gardens on Sage in the Ancient or Classical Period and unlocked the Wondrous Effects of that resource early in the game.  I thought this would prevent me from building a Sage Manufactory in the Early Modern Era, but I'm allowed to.  Not only that, but when I build it, it seems to outright steal Wondrous Effects from the Dutch.

I've played the next turn with and without building the Sage Manufactory, and the other empire's city growth is identical in both cases.  Do we know what happens in this situation?  Do we share the Wondrous Effects?  Did I steal it?  Did they lose it at some earlier point when they stopped meeting some requirement?

Below save file is from immediately before I buyout the Sage Manufactory in my city of Mbanza-Kongo.

Ottomans Turn 88 - Manu Theft.ctr