getting global var from other script in c#. Works in 1 project of the 2 projects, why?

So i have 2 projects. The “original” project en a “combined” project. The “combined” project is the “original” project + asset folder of other project.

In “original” i have a scene called calibcubus so i also have it in the “combined” project. When i run the scene calibcubus in the “original” project it works fine, however when i run the scene calibcubus in the “combined” project i get the error:
NullReferenceException: Object reference not set to an instance of an object

I dont get this cause the scenes are completely simular. Can anybody give me some advice how to solve this?

Found the answer. Appereantely every script which has this error in the “combined” project i need to remove from gameobject and then reattach it.