I see parts of UBlueprint have #if WITH_EDITOR, but not the entire object. It also doesn’t override IsEditorOnly (which by default returns false). The SimpleConstructionScript (which contains the nodes) isn’t wrapped with any #ifs, so appears to be valid in non-editor builds. The fact that you can spawn blueprint classes in shipping builds means the components/properties stored in the UBlueprint have to be available somewhere. It seems like either UBlueprint has to work in shipping builds, or the components and properties get moved out to another class in non-editor builds?