Warnings on End Play: GLTF not attaching to Tileset

I am spawning a Cesium global terrain actor (tileset)through Blueprints. In the Blueprint, I also attach a world CesiumIonRasterOverlay. This all seems to run fine, and the terrain and imagery are visible in game Play mode. However, when I end the Play mode, I receive ~15,000 warnings ( I guess every gltf in the globe) saying that the gltf could not be attached to the tileset as one is static and the other is movable. I’m not sure how to address this. Do I need to explicitly destroy the tilesets? Somehow tell the IonRasterOverlay to expect a movable tileset?