If you collation is Case Insensitive, then to only update rows when values would have changed, the SQL needs to cast to a Case Sensitive collation:

AND CAST( Import_Data_Fixed.LocationMixed as varchar(100) ) COLLATE SQL_Latin1_General_CP1_CS_AS

<> CAST( IDF.Location as varchar(100) ) COLLATE SQL_Latin1_General_CP1_CS_AS