When converting an st_geometry attribute using the sde.st_transform operator from one spatial reference to another, the st_geometry_columns table must be updated to reflect the new spatial reference.
Instructions provided describe how to transform the contours table's st_geometry attribute to a new spatial reference.
SQL> UPDATE contours SET shape = sde.st_transform(shape,3);
83 rows updated.
SQL> UPDATE st_geometry_columns SET srid = 3 WHERE table_name = 'CONTOURS';
1 row updated.
Tables with st_geometry attributes registered with the geodatabase should never be transformed to a new spatial reference. These operations should be performed through ArcGIS to ensure all metadata about the feature class remains consistent.