Problem trying to create media player group of all my Sonos speakers

Want to create a helper group with all my Sonos speakers in it. Went into system, devices, helpers. Added a group helper, selected media player group. I gave it a name, added my 12 speakers, and saved it. But there is a red error mark beside it and it doesn’t show up anywhere.

There is no entity name showing to refer to. And I can’t delete it. What have I don’t wrong?

I’m using HAOS, updated to 2024.8. Have the Music Assistant addon and integration installed. It’s those devices I’m trying to add into the group.

Same thing happened to me. I rebooted HA - and voila it was there with no red circle, editable and delete-able.