Trading Center Agreement Change Bug

[hobbs]

I had built my Trade Center up to level 11 and had 7 agreements. I upgraded the building to level 13, removed two agreements, and am getting the message that with 5 current agreements, my trading capacity is full and cannot accept any additional partners.

[Spartan]

It is possible that the nation you are trying to trade with doesnt have free trade slots. That error message is confusing, thats true.
I checked your trade slots, it looks good.
It means, those nations you are trying to trade with are full