AppResources.ResourceManager.GetString Producing NullReference Exception

Recently having an issue with GetString()

translation = AppResources.ResourceManager.GetString("SomeInvalidString",CultureInfo.CurrentCulture);

Is producing a Nullrefence exception.. In fact.. even if I wrap it as follows its abending my app.

                try
                {
                    translation = AppResources.ResourceManager.GetString("SomeInvalidString",CultureInfo.CurrentCulture);
                }
                catch
                {
                }

Anyone else noticing this?