To expand on what @PaulFarrow is saying. We utilize the Toolkit SymbolDisplay like this:
<forms:SymbolDisplay Symbol="{Binding Symbol}" />
This works perfectly in iOS, Android in debug and full builds.
UWP also works when running in debug but when we do a real Release UWP build, the symbols never display. The layer.GetLegendInfosAsync() call definitely returns symbols and we even put code in to replace null symbols with a SimpleMarkerSymbol if that property is null (there were not any but we are to that point).
@MikeBranscomb @dotMorten - could really use your help on this one if you have any ideas.
John.