PlaylistItems: list Returns playlistNotFound

When accessing a YouTube Music playlist, the API returns 404. I believe this to be a bug, because the playlist returns in Google's API Explorer. Can someone please look into this?

Example Pop Hotlist Playlist:

GET https://www.googleapis.com/youtube/v3/playlistItems?part=snippet&maxResults=50&playlistId=RDCLAK5uy_kmPRjHDECIcuVwnKsx2Ng7fyNgFKWNJFs&key={YOUR_API_KEY}

Example curl command for above playlist:

curl -i -G -d "part=snippet&maxResults=50&playlistId=RDCLAK5uy_kmPRjHDECIcuVwnKsx2Ng7fyNgFKWNJFs&key={YOUR_API_KEY}" https://www.googleapis.com/youtube/v3/playlistItems

Returns:

u'error': {u'code': 404,            u'errors': [{u'domain': u'youtube.playlistItem',                         u'location': u'playlistId',                         u'locationType': u'parameter',                         u'message': u'The playlist identified with the requests <code>playlistId</code> parameter cannot be found.',                         u'reason': u'playlistNotFound'}],            u'message': u'The playlist identified with the requests <code>playlistId</code> parameter cannot be found.'}}