Cycles lighting Principled BSDF differently on CPU and GPU working on a scene right now, where I used Substance Painter for a simple plane and plugged all my maps into the principled shader.

Turns out the scene is lit differently when rendering on CPU or GPU.
That results in flickering which is not tolerable.

The scene is exactly the same, I saved it and only changed the render device.

The scene uses filmic color management and seems fine otherwise, only the objects with the principled shader are affected.

I had to censor the character, sorry.

Any help would be appreciated.
OK I found the answer, really stupid mistake.

I had direct light clamping on 10 and it did really weird things where light sources would be randomly clamped out.

I could re-render the same frame several times and achieve different results each time.

I just turned it off now.