text: LOOKS LIKE OsmAnd+ PROBLEM (I'll leave this as unresolved for awhile, in case anyone has comments).
  The issue seems to be that it doesn't always render properly where areas overlap. In some cases, water renders on top of "park", in others, it renders as a sort of average of the water & the underlying area. It may be related to the "Live" updates. I'll put it to the OsmAnd developers. (for comparison, see river around Baker Park and downstream a bit on the left bank in Bowmont Park - former renders badly, latter OK).