While trying to upload changeset 33193763, I met this message: Error message(untranslated): Placeholder node not found for reference -13644 in way 48378769 As it's difficult to debug this from within JOSM, I saved the *.osm file and looked for that -13644. I found it twice in updates to two landuse=forest ways. I swear I did not update landuses, but I can't tell if one was attached to something like a way I touched up as it is their pesting habit. Anyway, it's not a reason for a dangling ref. I edited out those 2 ways updates, I attached them to this ticket, I reloaded the purged *.osm file and then the chngeset uploaded correctly. Hoping this can help. André.