"Position - Excluding Offsets" In "Opacity Mask" Causes Black To Appear

Hello!

I have an issue with the World Position and Local Position nodes when using “Excluding Offsets”.
It causes grey to appear in the material, and black in the game world.
I can get it to disappear in the game world when “World Position Offset Writes Velocity” is disabled, but then it exhibits the same issue when it starts moving.

The black in the game world says:
“YOUR SCENE CONTAINS A SKYDOME MESH WITH A SKY MATERIAL BUT IT DOES NOT COVER THAT PART OF THE SCREEN…”

I use it within the ‘opacity mask’ which is where I found the issue, and it does not matter where I put it, it still exhibits the grey colour even when it’s put directly into the opacity,

I am using Unreal Engine 5.3.2 with no additions.

Any help would be greatly appreciated!