Bug Different result for the same post process

Hi,
I'm making a 3D game and I'm having a strange issue here.
In 2 scenes (main menu & game) I have the same models, same camera, same lights, same post process global volume and I have 2 different results.
I don't know how it can happen, I have baked the lights, tried everything but the scenes still look different despite having the same settings :/

Any idea why, it would help a lot.
Thanks