Coastlines not updating in slippy map?

Is it normal that changes to the coastline take much longer to shine through on the slippy map than changes to other things? I re-drew parts of the coastline here and in the surrounding:, because it was really messy (ships at anchor being mistaken for islands, harbour piers quite distorted and so on), and then also mapped a few areas adjacent to the coastline. Funnily, the landuse areas are all there now on the displayed map, while the coastline wasn’t updated.

Afaik, the coastlines as rendered in Mapnik come from different sources. For a long time the OSM coastline data wasn’t usable because of the many errors it contained, so Mapnik uses US government data as well. But more and more zoomlevels now use the OSM coastline data…

Here is an email I found:

Ah, thanks for finding that. Yeah, that’s obviously the same issue. I notice my changes to the Attica coastline are also now slowly coming through at some points, bit by bit.

Yes, the coastlines are sourced from a shp file that’s irregularly updated. Best to ask Jon Burgess to update them.