"Modified Date" ? You have burned an audio CD. There is not date data in an audio CD. And no 'files' as such.
That date is something your computer has decided to tack on to fill the space in Explorer. The supposed CDA files are Explorer's method of displaying the CD tracks.
My XP computer says all CD tracks are 01/01/1995. All CDs - CD Architect ones, Nero ones, commercial audio CDs !
There is no problem - duplicate away with confidence ;- !