text: Hi. Last night, UK time about 4.00pm probably, 21 hrs ago? I drew a polygon, water=salt on the inside of the harbour. This morning I saw the same as you, some blue, some not. I also noticed the Polygon water=salt seems to be gone, removed?? not by me.
  So right about now ish, I got confused, and decided I was out of my league ;-)
  My guess is somehow my attemt at water=salt has been removed by someone or some process.