Lighting Needs to be rebuilt message after packaging

Hello everyone,

My team and I have run into a bit of a weird issue. All maps have been built correctly inside UE. We can run them no problem in editor. Once we try to ‘Launch’ or ‘Package’ and load the main level from the Title Menu, however, we start getting: “Lighting needs to be rebuilt”

We’re not sure why. Any idea where to even start with debugging this? Building is successful. Packaging is successful. The two scenes use different game modes however: Third Person Game Mode for Main Level and a custom Game Mode for the Title Screen (which has our HUD and no spawn).

All help appreciated. Thank you so much