Its either a UI error or a bug.
In game, Abassyds share the Garden Bounty (which doubles the food yield of bushes next to mills) trait with the Delhi Sultantate. This however, is not consigned anywhere within the civilization info (for example, the Learn to play section) or related material.
Maybe it has relation with both civs also sharing the +25% gather speed from bushes and the inability to collect food from boars.