A feature with a null or zero-ring geometry (e.g. GEOMETRYCOLLECTION EMPTY, or coordinates: []) produces no cells and can silently vanish from an audience or trade-area union.
Detection
Geometry is null, coordinates array is empty, or ring count is 0.
Mitigation
Filter and log empty geometries at ingest rather than let them drop silently
Alert when a feature count declines after a geometry-processing step