basically a reflection will no longer line up correctly with its source, the more lens distortion the worse the error, the reflection buffer is being distorted but the reflections themselves are maybe being calculated from pre distorted positions
when I do it after tonemapping the reflections are locked in already so it distorts correctly
looking at all the banding on blurry screen space reflections I’m guessing some aspects of these reflections are handled after tone mapping but before the post process blendables, but that is just a guess
I understand the center will be undersampled, but I think also the bit depth has something to do with how smooth the result is, maybe if not to upsample resolution maybe some way to do the distortion in 10bit after the tonemap? then back to 8bit again afterwards?