Just realized today that I'm having this issue too. Not so much that I'm having fps issues, but rather that my gpu usage is way higher than it should be across the game (mainly outside of orbit). I'm getting 80% usage while on the lowest settings, which is obviously not right for a RTX 2070. Looks like the issue has been identified (that its related to lighting), but I'll still post my info anyways. I don't remember having this issue before beyond light either. EDIT: nvm, I figured out my issue (had nothing to do with the game)