I came across interesting behavior when setting up a ShartTools dashboard to play Sonos playlists. The bug is with how SmartThings is integrated with Sonos.
The primary bug being that if you click a favorite for Sonos to start playing, it does not clear the Sonos queue first.
If I start with a clear Sonos queue the playlist is added. If I then click another playlist it seems to add the playlist and shuffle the queue. So now the queue is made up of any songs already in the queue and the newly added playlist.
James from SharpTools did some additional testing (I confirmed the same) and found that if the Sonos queue is not set to shuffle, the new playlist is added to the end of the queue and starts playing from the first song of the newly added playlist. So from a user song playback perspective, this is only an issue if you have your Sonos queue set to Shuffle.
I confirmed via the Sonos app directly, if you add a playlist it does clear the queue before adding it.
In the scheme of things this is a small bug, but I thought others may benefit from knowing it exists. I created a SmartThings support case for it, so maybe it will get addressed in the future.