How to force Post Processing to ignore RenderTexture?

Hi
I have downloaded and set up PostProcessing 1 and 2. For now I was testing them so I have both of them applied to the main camera, but one of them is inactive, but I'm simply able to switch between them anytime but I have a weird problem. I have a portal in my game - a 2nd camera which is rendering the other part of my game to a texture and a material is showing it but the problem is it passes post processing inside the portal, but portal camera doesn't have post processing attached to it. How can I remove post processing from the portal view? I simply want to remove post processing there and add different, with sepia, bloom and so on.

And btw. is this normal that two render textures (two sides of portal) in my game are dropping frames in game?
I was following this guy:

Here is how does the portal look in my game (wrongly, because post processing is inside!):

 

I arrived here because I have the same thing.
My postprocessing from the player camera is overlapping the postprocessing from the portal camera and the picture is double color graded (has a big contrast and blur).
What I have done here - I just turn off the postprocessing of a portal camera.

So what you need. You need a 2018.3 and PostProcessing Stack v2 (download it through the Package Manager). You need a (portal) Camera with PostProcess Layer attached with the Layer parameter is set to Nothing. And a gameObject with PostProcessing Volume there you set up the thing along the postprocessing. It is how it works in this version of unity.


Now if you want several postprocessing things, just to create a couple of gameObjects, attach to this a postprocessing volumes, assign a different postprocessing volume profiles and flag this gameObjects with different Layers (create them before). On the Camera objects go to the PostProcess Layer component and choose these layers in Layer parameter, in each cameras respectively.

P.S. To solve my problem it was necessary to have two different postprocessing volumes. In the second one I have to turn only Color Grading feature off.