Setting the useLegacyLights and the 2 other variables you suggested works. But that means we are basically reverted back to old versions. And useLegacyLights is being removed soon. I think its an issue with the renderTarget/reflector not using the same values as the default renderer outputs. Even without any fog the issue exists. Doesnt that mean its a bug or unintended by three?
https://codesandbox.io/p/sandbox/ocean-forked-3yd5pt?file=%2Fsrc%2Findex.js
There are all using default values and the output is not correct unless i revert all the stuff you suggested. So does that mean that reflector/render target has different defaults from the normal renderer in three js now? I dont understand why making those 3 changes fixes the reflection in this example.
I even created a custom reflector where it literally just sets the frag color to the reflection and its still the same. So i think there is a difference between how the render target and renderer now process/output colors.