Nile's mouth rendering problem

[kocio-pl]

Expected behavior

There's a strange artifact with rendering Nile's mouth, on OSM Carto it looks like this:

https://www.openstreetmap.org/?mlat=30.9&mlon=31.116667&zoom=8#map=17/31.52605/31.84572

Actual behavior

German version looks like this:

[giggls]

Most likely caused by the fact, that natural=water is rendered from the database while coastlines are rendered by a shapefile from https://osmdata.openstreetmap.de/

This does not happen upstream because German style uses Water polygons and a grey background while upstream uses land-polygons and a blue background.

I do not think that the watercolor stuff from @imagico is causing this.