Is there any chance to send us your file and playlist?
As you said you can reproduce the issue with the playlist song1 I would like to have the following files from your USB drive:
#Playlists folder including all of the files inside (the best is to zip the entry folder)
MultiTrack/your song 1 from the playlist. Here you also need to zip the song folder.
Could you please send me those files (using we transfer etc) to the support_at_cymaticaudio_dot_com address?