I have reported this problem also under another question:
When using SetFeatureVisibility(listofids, false) inside a Layer and calling PrintTask.PrintAsync the Features don't disappear inside the (pdf, gif etc.) document. I also tried using DefinitionExpression which has the same effect.
The features disappear on the MapView!
We are using Arcgis Runtime SDK 10.2.4 for .NET.
We really have a problem with this. Any help is appreciated.