Ducal Stable bonus applies to livestock WITHOUT a pasture

I just noticed playing as Casimir, that when I have improved one of several livestock within a city's reach, and built the Ducal Stable, the bonus from the Ducal Stable applies to the unimproved livestock as well. In the save, it is seen in the city of Wroclaw. The Ducal Stable description clearly states that the bonus is only applied to pastures, which in this case is false.

This has always been the case for Stables. The bug is that the Ducal Stable is misdescribed.