Hello @RogerCC, welcome back!
I am sorry to hear that the order of your Favorite Stations has changed in the Sonos App. Although I am not sure what could have caused this change, I’m glad your PC Sonos App still has the order you desire.
The order of the Sonos Favorites goes the same way as "Recently Added".
Could you or anyone in your household with access to the Sonos App and with your Sonos Account credentials maybe removed and then re-added some stations to the Favorites list?
I’ve marked this thread as a feature request, a way for the Sonos users to be able to adjust the order of the content in the Favorites section and all subsections there as well within the Sonos App, and forwarded it to the appropriate teams for consideration.
I hope this helps.