Level blank after switching levels

I am building a game with a couple different levels, a third person one and a flight sim one. The flight sim level is the default beginning level in the editor. When I go to edit the third person level from the flight sim one, everything loads fine. When I go back to the flight sim, all the assets disappear. The lighting also switches from night to day (I’m using the default skybox). The same phenomenon happens when I send the character to the flight sim level via a box trigger. Restarting the program returns everything to normal. When I switch back and forth again, the assets disappear again. Any help on what is causing this?