I don't remember how this worked in EWoM, so maybe it's working as designed.  But it still seems odd.

I offered a trade treaty to Altar.  They wouldn't accept it unless I offered 21 gildar to go along with it.  With that, they accepted it.  I checked the economics tab on the govern window, and it told me that both Altar and I were benefiting from a 10% increase in gildar due to the treaty, which netted out to +3.1 for me, and +.5 for them.  So far so good.

Some turns later, Altar contacted me and asked for a trade treaty.  They offered 58 gildar to convince me.  Didn't we already have a trade treaty?  I accepted, but the govern window still shows 10%.  So no additional benefit other than the 58 gildar, I guess.  But then I noticed that a road had appeared and a caravan was moving between my city and theirs.  That hadn't happened after I offered the treaty to them, only after they offered the treaty to me.

Seems confusing.  Is this working the way it's supposed to?