Update: this is broader than Button devices / cloning specifically. We’ve now hit the exact same crash (same ensure, same signature) from an Import operation as well, with no duplication or copy-paste involved. Combined with the related report at Error: Incorrect owner passed. Scopes are mismatching! (triggered by Alt-drag duplicating a plain Prefab Entity, no Button device involved), the common factor looks like the generic OverriddenPropertySet owner/scope handling whenever an actor/entity carrying overridden-property data gets attached to a new owner — via duplicate, copy-paste, or import. Button devices were just the easiest case for us to reproduce reliably, not the root cause.