Latest (08/06/2024) app and firmware.
Browse library to a song and start playing to a device, or group, with the play button. Music starts, confirm the queue by expanding the device from the bottom screen, view the queue list from the bottom left list icon. Queue shows the playing song. Return to the library and browse to a 2nd song (or album). Select "Add to End of Queue" or "Play Next". Dialog pops up with "Added to Queue". Expand Device from the bottom again and select the Queue list from the bottom left. The Queue list shows "Unable to load. Please try again".
No matter how many times you 'try again' the queue is not displayed. The music plays on and even the newly adding song(s) will play. There is no way to get the queue to show up (and no way to clear the queue on Android), adding new songs doesn't do it, selecting a song to "Play Now" doesn't do it. This view of the queue will persist. What will 'fix' it is if you select a new song (album) and select the play button, or select "Replace Queue" then the queue is replaced and the queue list is now viewed with the updated songs, but the old list I was trying to curate for the evenings listening is gone.
So, "unit test for Add to End of Queue bug fixed sir. Pat: well done son, ship it!. I do hope the 100's of Ace customers are giddy with their ability to swap the audio with their sound bars.