AI unlimited trade unit bug

So the AI is just " smpamming " trade units , apparently for free too , over 30 trade routes ,and captured a city the "caravan killed" couldn't fit the screen , oh this city was just 3 or 4 turns out of resistence .

I've noticed it too. I wonder why they don't all do it. The ones that do it are usually successful. I can't comment on the free thing.
Fix suggestion?

Go to play CPP,
This mod has been abandoned