Yes, we apologize for that. That's a known bug, but we haven't had the time to look into it properly.
I added a disclaimer to Kon's post; but for the time being, we recommend just saving the map right before adjusting environmental settings - just in case.
DOF also makes a automatic backup by saving a .dofbak that you can rename .dofscn if you need to revert. But this backup may not be as current, so still save often.