When I add a song to the queue while advertising is playing the queue gets deleted, and only the song I just added is left. It's like I just replace the queue with the new song.
This has happened several times now. But since I've already wasted hours trying to recreate my queue I haven't experimented with if it happens everytime I add songs during advertisement, or just sometimes. Or if it also happens sometimes during normal playback. But at least 2-3 of the times it was while advertisement.
Device: iMac, late 2009
Operating System: macOS 10.12.6