Post Processing Fog of War keeps drifting depending on viewport size

[Deenhan]

I am currently working on a fog of war. I have utilised a few tutorials but have had to alter a few things to work how I want it to.

The fog of war utilises a post processing volume with a material (M_FogOfWar) to do the fog of war effect. Inside of M_FogOfWar, after attempting to align it to the centre of the map, it takes the two render target 2Ds and lerps between them for the fog of war effect.

This is how it is supposed to look, and looks in certain sizes of the viewport :

[Deenhan]

However once the game is built, or the viewport is changed, it looks like this:

I’ve been trying to fix it for a while now but am completely lost. Any help would be greatly appreciated.

[Deenhan]

This is the main material (M_FogOfWar) being applied to the post processing material.