text: Well I'm confused :)
  https://a.tile.openstreetmap.org/18/128455/83484.png is now OK, but some tiles at some scales aren't.  I'm not sure if it's been changed from OK to not OK or back, since the rendering queue is pretty busy at the moment nad https://a.tile.openstreetmap.org/18/128455/83484.png/status just says "last rendered and accessed yesterday".
  Of the 4 "walter=salt" in BG and Ireland this is the only one inland of the coastline.  There's no reference to "water=salt" in the OSM Carto code as far as I can see.