Help with simple Shortcut for Playlists

[Julien]

Trying to make a simple Siri Shortcut that would take 3 (or any multiple of) Playlists and combine into 1 Playlist. When I run the Shortcut I only get the tracks in the last Playlist (The New Rock in this example). The preceding (Breaking Rock & A-List: Alternative in this example) Playlists tracks are MIA in the new Playlist (Master Rock in this example). In the example there are 50 tracks in each Playlist so the Master Rock Playlist SHOULD contain 150 tracks but it is only 50 from the last added Playlist. Also I get this weird error??? message when I run the Shortcut (all Playlist and tracks are downloaded onto my iPhone).

Same behavior if I run it on my iPad.

 

[Julien]

Where could I post this question that people know a little about Shortcuts? Would love to get this simple Shortcut done.