Roon ARC is handling add to queue wrong, when adding a playlist. When you add a playlist to the queue, then playlist starts playing and the queue is gone.
Describe your network setup
Roon Nucleus one. Rest is irrelevant for this issue.
Thanks for writing in and sharing your report! I have some good news here in that our team has already identified a fix to this issue, and the fix is waiting for release.
So you should see this issue resolved in the next update or so! Thank you for your ongoing patience until then, and certainly let me know if you have any questions!