The SwissCenter database can become corrupted causing unexpected behaviour. Messages will be present in the logfile indicating that a database action has failed but this will not be obvious to a typical user.
To fix a corrupted database an experienced user could use MySQL Administrator to repair and optimize tables.
It would be preferable to have a new Database Tests option in the Installation section of the Config which would identify any tables in need of repair. Tables could then be selected which options to Repair and/or Optimize those tables.