Fog rolling in performance issue

[Rex]

As I was progressing through the game sometime near lv20 I had fog come in and my framerate went from stable 60 (capped) down to 30-40 fps where ever there was fog in the main base or stages.

This ran poorly on all quality settings even lowest.

This performance impact also seems to go away after some time or after game restarts because at this time foggy areas dont run as poorly, This might be an issue specifically with the first time players see fog until a game restart.