I am seeing more edits to the coastline again, moving the natural=coastline boundary from the correct place at the coastline into the middle of some water areas. See here for instance. Sometimes the coastline is not easy to identify if the coast is marshy or so, but it does not go straight through the middle of some larger body of water. Please refrain from doing these kind of changes and revert the recent changes. These changes are blocking the processing of the OSM coastline data at https://osmdata.openstreetmap.de that basically everybody relies on to get good coastline data for their OSM maps.
You can see the cases where the coastline is today significantly different from the coastline two weeks ago here. Some of these cases are probably okay, but some are not and they need to be fixed before coastline processing can resume.
The coastline is a rich and complex environment at the edge of the marine environment including cliffs, beaches, harbors, headlands, bays, wetlands and islands.
(this second one seems to be copied from some dictionary, because it doesn’t seem to make a lot of sense in the context of OSM to include these other features, either you include bays and describe the water side, or you describe the land side and include beaches, islands and headlands).
mean high water springs