For several months I have succesfully used the following formula to identify duplicates values in the Program ID column.
=IF(COUNTIF([Program ID]:[Program ID], [Program ID]@row) > 1, "Duplicate", "Unique")
Program ID is a formula generated column using the following formula.
=[Site Num]@row + "." + ProgNum@row
A recent Smartsheet update has broken this formula. As you can see, 22.01 should throw a duplicate value but it does not.