Fatal Error In Mode Scenario During Update Within Windows Manager While Modifying Ai Or Adding Smth

so i've been trying to modify the ai in a game scenario and adding the wagons so i can couple them but then something is off, when i try to do that, the game crashes with a error that says "fatal error in mode Scenario During Update Within windows manager" it happens to any route like route transylvania v3 for example, and also, i have nothing corrupted in the game

 

Think you always have a problem

 

so?

 

The last post in this thread seems to suggest there is a problem with an Asset
https://steamcommunity.com/app/24010/discussions/3/4204742681383682501/

"This means TSC hits a corrupt blueprint (.bin, which is serialized .xml data) it can't process, which is the fault of the asset provider."

Try creating the scenario using Only items you have bought thru Steam.
If you are able to create the scenario than it in one of the other Non-DTG assets you are trying to use.