I\'m developing a Windows Phone 8.1 app that also targets Android(Xamarin)
As ever I added my string resources(.resx) on a PCL and referenced them on my launcher project
I had the same behaviour. Today I created a new PCL Library (with another name) and copied the resx file to this project. I modified all references and everything just works fine in my WinRt (Windows Store) App now!
There was the string 'resources' in the portable class library name. Perhaps this was the problem!