Hey wheel -
Thank you for your report. I will begin investigation into this issue as soon as possible. Can you let me know what version of the engine you are using and feel free to edit your post if you have additional information to provide, a good template can be found here:
How do I report a bug? - Programming & Scripting - Epic Developer Community Forums
Also please let me know what types of lights you are using in your scene, are they Static, Stationary or Movable?
Thank you.
Eric Ketchum