Some bloom shaders darken the screen

I've used shaders like NeoBloom on another PC before and it worked perfectly. Lately I tried it on my new PC, and I noticed anytime I add that shader, the screen will darken a lot. Its not just NeoBloom, a few other Bloom shaders darken the screen like this, but not all of them. Any idea what could be causing this? I've had this happen with all 4 rendering APIs. 

(This is my first post here, so apologies if the images are too big or this is in the wrong place. Might need to resize the images in the future.)

No Shaders



NeoBloom