Texture images are brighter in material editor, and affect the mesh?

I’ve exported some textures from Substance and I’m trying to manually set them up (as opposed to using Source, which I normally do) and for some reason, the material images are brighter when in the material editor, compared to the original file which appears normal in every other instance.

As you can see, the image on the left is completely different than the one on the right. The preview mesh is also incredibly bright, and I was guessing the scene lighting might be affecting the texture somehow, but that doesn’t want to change, using the settings for brightness etc. I’ve checked the image settings referring to other working Substance textures and everything is the same, so I don’t know why this is happening. Help.

Make sure you’re following this guide

Particularly that sRGB is unchecked on the OcclusionRoughnessMetallic texture.