Okay… so regarding the glowing light that @Ozykz posted about above… It seems like it has something to do with the material editor.
This is sort of difficult to explain but bear with me here. Consider the following actions:
A: Changing the material (can be as simple as just moving a node)
B: Applying the material (pressing the apply button)
C: Saving the material (pressing the save button)
D: Building the Lighting
Depending on the order you do these in, the lighting build will produce the glowing light error. Testing different orders of these tasks shows:
ABCD - 
Glows
ABDC - 
Works Correctly
ACD - Glows
ABD - Works Correctly
From what I can tell, it doesn’t seem to make any difference what the material logic is doing (as you can see from the video, literally all I am doing is moving a node). The only thing that matters is the order of saving/applying the material and building the lighting… I did test this with material instances, so long as the parent material works correctly the material instances (appear) to work correctly as well. If the parent material is glowing, the child materials will glow.
Nightmare bug tbh