Hi @SirDigitalKnight
Thanks for your post!
The app’s list of favourited playlists is maintained by the speakers - it seems, for some reason, the info is not reaching the app. I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.
Before doing so, however, I would definitely recommend trying a reboot of your router by switching it off for at least 30 seconds. Rebooting your speakers afterwards may also help.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein