Sometimes when I bring in a new object or duplicate an existing one, a large duplicate of that item appears in the skybox. When I move the original item, the skybox item moves with it. This glitch can happen with any object, from the finishline to decorations. This has also happened where a segment of track was blown up in the distance but was missing from the actual track.

Another quick question- decorations and obstacles don't appear when I playtest the level, is there a setting for that?