SQL ‘stuff’ and ‘FOR XML PATH’ generating strange symbols

If you modify your use of For Xml Path, it will do the unescaping for you and you won’t need to resort to using the Replace function:

,   Stuff(
        (
        Select '; ' + IsNull( D2.SelectedComments, '' )
        From #StudentDetails As D2
        Where D2.Stud_PK = A.Stud_PK
            And D2.CourseNo = A.CourseNo
            And D2.Section = A.Section
        For Xml Path(''), type
        ).value('.', 'nvarchar(max)')
        , 1, 2, '') As SelectedComments