So uhm... I do play a lot of modded civ but has anyone ever had the same issue?

1. You make a Trade route
2. You trade for a few turns
3. The Trade route finishes so you send the unit out to trade again
4. You notice that your Trade route connects to a comply different city then you clicked
5. You now have 2 Trades routes
6. These Trade routes keep duplicating themselves above the Trade route limit until there are no aviable Trade routes left
7. You have currently 31 out of 5 possible Trade routes ongoing with other civs.

So uhm... I am a huge fan of playing fairly. Does anyone know what could be the cause of this? I had this issue once before but it simply went away after a bit trial and error and now it's back. I can tell you it is not connected to a modded Civ I am choosing to play. It happens with every Civ.