Does anyone know when or how these happen? Just an JOSM>API glitch in which somehow a double delete/undelete action is included in the same API request? (somehow similar to the good old “manual undelete”)
Edit: I should add that no delete was intended by the editor uploading the CS with rev2.
Please explain what you mean with “elements in question is still valid and in place”. The database says that way https://www.openstreetmap.org/way/667327612 was deleted, so I assume you want to express that the mapper did not intent to remove the way. It is VERY unlikely that JOSM sends a delete to the api without telling the user that this will happen, so I assume the mapper simply did not double check the list of changes before uploading.
The next thing to do is to revert eihter the full changeset or only a part.
OSM never remove objects from the database. Deleting an object in OSM means basicaly changing the tag “visible” to false so it won’t show up in the map and won’t be transmitted if you download data from the database.
All correct, it was my (rather stupid) fault. iD somehow managed to submit a changeset twice and thus created duplicate entries. Obviously a later JOSM edit in the same area filtered the duplicates. Only now noticed there existed 2 identical entries at some point. Will refrain from using iD on bad network link, promised.