Messed up colors when using OutputPass

[atul-livspace]

Description

When using output pass, the colors are not obeying the Color values set to the objects and the scene background.
Here's the rendered image for before and after implementing output pass.

Before:

After:

Notice how the color of the background and object changes from what it was originally set.

Reproduction steps

1. create a scene setup
2. add EffectComposer
3. add passes: RenderPass and OutputPass
4. compare the output by disabling and enabling the OutputPass

Code

composer = new EffectComposer( renderer );
const renderPass = new RenderPass( scene, camera );
composer.addPass( renderPass );

scene.background = new THREE.Color(1,1,1); // pure white 
const outputPass = new OutputPass();

// try commenting below block of code and see the color different.
composer.addPass( outputPass );

Live example

https://jsfiddle.net/zLne9hc5/

Screenshots

No response

Version

r159

Device

Desktop

Browser

Chrome

OS

MacOS

[Mugen87]

Duplicate of #27184/#23019.