Eifelkobold!
Hello, after some time consuming outdoor research (not for the place of the note this was easy...) I can confirm this note. But I guess the creator reffers to the track not to the B477. After the flood in July some of the old mineshafts in this area collapsed. Immediately all ways were closed due secruity reasons. I added the informations in Changeset 115110647 (https://www.openstreetmap.org/changeset/115110647).