I suspect that I I may have just found a bug that is related to this. It would be nice if someone can confirm it. Here are the parameters:
Game: 8 AI persona, all normal; Medium size spiral, turn 173 - I am playing as the Terrans and am in first place, version 1.03
Start dialog with AI in second place (Altarians for me) and select trade
In the following order
1. Add all technologies
2. Add all ships
3. Add all starbases
4. Add all planets other than homeworld
6. Add all trade resources
At this point the AI's response is 'You must be joking'
5. Add Make Weekly Payments of 100000000 (sufficient to roll over internal limit, you will know as it resets to the max value) From AI to player
Now the AI's response is the emphatic great deal and there is nothing in the Player trade window.
Accept the offer and repeat with new second place player (Krynn for me).
Some interesting things of note:
1. The Gain column is not formatted to handle all of the trade content, it ends up spilling over the treaty box
2. The Weekly Revenue From Treaties number box is too short to handle large amounts of bc ( 1 000 000 covers up text)
3. After acceptance of the trade for the Altarians, the Net amount shows as 0 bc. Unfortunately, I do not know if this happened before or after the second trade.
On turn 174 repeat above with new second player -- Income per turn now ~1.9 mil
On turn 175 credits go negative (-1385726) and all production is shut down. I still show incoming funds of ~1.9 mil per turn.
On turn 176 credits are positive again (532034) and production is up.
On turn 177 credits go negative (-1845783) ....
I suspect that the credit counter is overflowing.