That is because you are using the file backup method where you do have the right to exclude / include folders. We are aware that the "refresh" of this window is not always doing its job well, and that it sometimes keep telling us that it does volume level backup... When you continue, you normally should see it correct in the summary.
Our DEVs will hopefully fix this window in a later update.
Thanks for letting us know! It is not because we knew this one already that we know about all of them