New coastline way/1449436936 duplicates the existing one way/1447932542

IDK, what should remain here (different roles in Relation).

You change breaks coastlines. Please, read Wiki about natural=coastline tag. Fixed here changeset/174265883

Your changeset is not good:
- Please, read the OSM Wiki about tags. natural=coastline is not suitable here
- Add type defining tags if the point ("Localita mercury") means something (hotel, shop, amenity, etc)

Отлично! Я пока удалил natural=coastline. Вкратце, он предназначен для материк - море/океан.

No problem, I've already fixed.

natural=coastline специфический тег, пожалуйста, прочитайте wiki, прежде чем его назначать.

Coastlines are broken with this change ..

Coastlines are broken after this changeset.

Coastlines are broken after this changeset.