Another addition: A mass closure of Iranian notes was done a few months ago: https://resultmaps.neis-one.org/osm-notes-country?c=Iran

To me it looks like this is the problem: https://github.com/osmlab/onosm.org/issues/127

Looks like there already is a bot that closes useless notes (see: https://www.openstreetmap.org/note/3969523)