Do Treasure fleets passing through City State territory cost a financial penalty? Or is this a bug?

[xphantomx]

I honestly don’t know if there is some game mechanic I’m unaware of:

As you can see I have a Treasure Fleet on the right ready to move into a navigable river through a City State (who I am suzerain of) to unload its treasure in my territory.

I moved it in ready to click unload

I noticed after I clicked unload, it gave me +300 gold but then lowered my gold per turn substantially

So I wanted to make a bug report because that made no sense, but then I noticed while recreating it to take pictures…it wasn’t unloading the treasure at all that caused this. It was simply moving from the ocean into my territory that lowered my GPT substantially.

It only seemed like it was the unloading because of the bug that you have to refresh by clicking on something else in order to see yield changes that happened. The unloading was the refresh.

But as you can see here, after moving in the Treasure Fleet, I refreshed the screen by clicking on my city center and the GPT is already decreased

So why did I lose so much gold per turn yield by simply moving my Treasure fleet along that river? What triggered it?

 

[WeirdDud]

As far as I'm aware, there isn't a passive gold income attached to treasure fleets.

If I had to guess: your gold per-turn was truly 728 as of turn 126, and for some reason the UI didn't repaint until you moved the treasure fleet.
As for the true cause of losing ~300 GPT since the previous turn, it could be a number of things, such as a celebration ending if you took Plutocracy as your government.