In Strategy Developer 10.x, some tables that are already being used in the project, appear again in "Tables available in the database instance" window in Warehouse Catalog, as shown below:


If importing the table through the warehouse catalog, duplicated table with name "<table_name (1)>" is created:

This issue happens when physical table objects become managed objects.
The root cause is unknown, in order to track down the cause of the inconsistency, customers encountering this issue should make note of Schema-related changes, Object Migrations, or error messages prior to experiencing the problem. Change Journaling, if it has been enabled, can help in preserving this information.
Contact Strategy Technical Support for further assistance.