Add on cars breaking upgrades on a few Cunning Stunts vehicles

[nkjellman]

I have noticed that when I have my add on cars installed, the upgrades stop working on 3 vehicles from the Cunning Stunts DLC. These are the vehicles.
-le7b
-trophytruck
-sheava

Does anyone know what is causing this? I checked the carcols.meta for my add on vehicles, compared them to the Cunning Stunts one, and I have not found any conflicting ID's.
Does anyone know what else could be causing this?
Could there be another parameter I need to check?
Has anyone had this happen before?