problem with Export | Alter SQL script

[Al Lombardo]

After I Export|SQL Create my schema, I shouldn't have any changes if I immediately do an Alter script. I, however, always have one change which always come up. The SQL alter drops an index and re-creates it as a unique index on a table called status. I've checked the SQL created by the SQL create and it is defined as a unique index. Every time I do an alter script, I need to remove this entry from the script. Any ideas as to why this table always generates a change?