With all the automatic features/options turned on for metadata, the updates are not immediately reflected in ArcCatalog's metadata tab after editing versioned data in ArcMap.
This is a known limitation.
The metadata is updated, but at the moment, the update can only be seen by doing one of the following:
▪ Disconnect and reconnect the Spatial Database Connection in ArcCatalog; view updated metadata,
▪ Switch to a new version (by way of Connection Properties), and switch back to original version; view updated metadata updates.
At version 9.3, refresh the connection (right-click on spatial database connection > refresh).