The Dn table does not contain business table attributes, only the An does.
The root issue here is using database tools on tables registered with the geodatabase. You need to be very careful to avoid corrupting geodatabase metadata (field sizes are maintained in multiple locations within SDE and GDB tables).
Best practice is to only use geodatabase-aware tools for these sorts of changes (or unregister versioning, clone the table, drop the table with ArcGIS, rename the clone, alter the clone, then re-register it and re-version it).
- V