On the changeset comment, that will be either because I am making changes to the map in the same changeset I am fixing phone numbers not in the international format from the associated MapRoulette challenge, or because I've recently done so (the changeset comment sometimes seems to persist between changesets). You can find more information about that at:
https://maproulette.org/browse/challenges/7750

To resolve this, I will try to keep any future MR changesets exclusively for those tasks.

The other (main) parts of your query require more in-depth investigation on my part before I can answer you. Thank you, though, for bringing it to my attention. My initial suspicion is that these were changes suggested by iD while I was doing editing to that element/in that area, though I can not confirm this until I have done some investigations, and it is just a hypothesis. I apologise for the inconvenience and confusion caused.

To attempt to resolve this, I will perform further investigations, and put another comment on this changeset to let you know what I discover, and what I will change going forward.

OK, thanks for the clarification.

osm.org/note/2622390

osm.org/note/2622386 needs checking

osm.org/note/2622387 partially

osm.org/note/2622388

osm.org/note/2622233

osm.org/note/2622238

osm.org/note/2622379

osm.org/note/2622381

osm.org/note/2622241

osm.org/note/2622380 partially

osm.org/note/2622383

osm.org/note/2622385

osm.org/note/2622384

osm.org/note/2622231

osm.org/note/2622230

osm.org/note/2622232

osm.org/note/2622234

osm.org/note/2622378