iCloud web interface - Notes - sub folders are no longer visible.

On my iPhone 8 Plus ( IOS 15.1 ), in Notes app, I have folders and some of the folders have sub-folders which contain some notes. However when I log into icloud web interface at https://www.icloud.com/notes/ I see only the root notes folders and don't see the subfolders. Few weeks ago all was fine. This phenomenon is new. Tried on several systems, with Windows 10, using Google chrome, Mozilla Firefox and Microsoft Edge, but didn't help. If I search for a note, it finds it and tells me in which sub folder it is. But these sub folders are not listed on the side of the web page of the icloud notes website. Any ideas?