Objects disappearing when changing scene

When I play my game the objects are visible and interactable. I then change the scene and come back to the original scene, and my objects are not visible but still in the scene. I changed the layering to a custom layer (ground, on ground, in air). The objects are still not visible. Can somebody explain why this is happening?

Found that if I raised the lamps on the Z axis that they stopped disappearing. I’m not sure if this explains the problem, but it did offer a solution.