Weird "UnassignedReferenceException" error

I am instantiating objects to use as a visibility thing when the object is between the player and the camera.
Everything works, I’ve done this a couple of times before, but for some reason I’m getting this error:

UnassignedReferenceException: The variable nonOccludeCollideRend of ObjectOcclusionController has not been assigned.
You probably need to assign the nonOccludeCollideRend variable of the ObjectOcclusionController script in the inspector.

The object it is referring to is there, but I can’t figure out why it’s saying this?

If I check nonOccludeCollideRend is there with:

if(nonOccludeCollideRend)

it is fine - I’m declaring the nonOccludeCollideRend, and then in start trying to instantiate it.

Is the order of doing this incorrect - there is a single error (so it’s not counting up), but it’s obviously trying to access it before it is declared, however it is in Start() which only runs through once?

Schoolboy error - the script was assigned to two objects in the scene. Heheh (shame).