Problems with Delta do Amazonas

Hi!

Context: I'm using the Android library Mapsforge to display OSM maps of each Brazilian state inside a native Android application. I get each state map from here and convert them from .osm.pbf to .map using Osmosis. The app uses only one map, of the state the user is currently living in.

Mapsforge use render themes files like this to determine what color each area should be painted as, how captions should be rendered, etc.

Problem: I'm having problems rendering the Delta do Amazonas region. All the islands inside that relation are responding to "natural=water" and not responding to "place=island" (therefore being painted as blue, same as the ocean and other bodies of water), while the water part of that relation is being shown as land, not responding to tags like "natural=water", "waterway=*".

I can't figure out if the problem is the render theme file, the original map file itself, or maybe the conversion process.

Here's a screenshot of the app showing the Delta do Amazonas region.