Trade Route Bonus Questions

I have two questions:
How exactly is the bonus value for recourse diversity calculated? I have Silver, Citrus and Wine, and am sending a trade route to a city-state that produces only Ivory. The tool tip for the trade route says that they are receiving a bonus to trade income, and I am not.

The other is, when does the Moroccan bonuses to trade routes apply? Only when you receive a trade route?

If you are playing Morocco, chances are that civ has a Market place in the city it's saying that they are receiving a bonus to.

If these are cargo ships, you'll want a Harbor present in the origin city for you to get max bonuses.

Both the available screen and the list on the cargo ship / caravan are supposed to include effect of all bonuses including UA.

Note that it appears that if something happens that should increase the bonuses during an active trade route, it doesn't appear to take effect in the middle of it, and you have to wait for it to renew to get the new higher bonuses.