First off! This has been a lot of fun and this is my first real stumbling block
I have ran into an issue when I run back into a portal where the variable spawnPoint of Portal has not been assigned . You probably need to assign it in the inspector blah blah…
It is assigned in the inspector. I have tried deleting, reverting, reapplying prefabs and it only happens when I try to go backwards in the scene 1 to 0.