When Amazon Redshift is the data warehouse type, attribute names that contain the open parenthesis character "(" are not supported. If any of your attribute names contain the "(" character, you should remove it before creating the data warehouse tables.
For information on renaming attribute names, see Add an attribute to all Satellite tables and the Hub table.
Discovering new tables does not affect existing entities in the model, even if there is a relationship between the new entity and one of the existing entities. For example, in the source database, Table 1 has a Foreign Key that points to Table 2. If Table 1 is added to the model and then Table 2 is added later, Table 1 will not be updated to contain the required Foreign Key.
The data warehouse needs to be "adjusted" when deleting a relationship/attribute from the model and then adding the same relationship/attribute back to the model. However, the "Adjust" operation deletes the data from the corresponding data warehouse column.