thanks for sending this basic example. It helped a lot!
The issue is connected with the scene naming. When you load and replace you main scene its “Scene” becomes “./hot_tub_configurator_play.gltf.xz”. To fix it do one of the following:
1) Specify “Scene” as scene alias in the “load puzzle” (check it out in the “gear” settings).
2) Specify “<none>” in the “export to gltf” puzzle. This option means export current scene, no matter what its current name is.