Skip Duplicates feature not working properly

[ReverendEntity]

Plan

Premium

Country

US

Device

desktop PC

Operating System

Windows 10 (latest updates)

My Question or Issue

I have been maintaining several playlists of recent tracks from JQBX rooms.  I normally load up the desktop client, go to the recent playlist capture and copy all the tracks into a larger playlist for that room.  Spotify will ask if I want to skip duplicates, and I always say yes.  However, after sorting the resulting "master" playlist by name and paging through it, I still find duplicates.   Sometimes it's the same song from a different release, which is understandable, but there have been several instances where it has been THE EXACT SAME SONG AND RELEASE.  This suggests that the Skip Duplicates feature isn't working as well as it implies.  I would appreciate it if someone looks into it.  Thank you!