UMG widgets with instanced properties reset those properties to default on compilation

This is perhaps a misuse of Instanced properties but the repro info is good so I thought I'd better add it to Jira. See Additional Info URL for details.

Checked and happening on:
//UE4/Main CL-2884111
//UE4/Release-4.11 CL-2885916

1. Open UE4Editor.exe QAGAME
2. File > New C++ Class > select Widget as the parent class > Next > Name it "CreatedWidget"
3. In VS, set up the following:

   UCLASS(editinlinenew, DefaultToInstanced)
   class UInstancedBase : public UObject
   {
   	GENERATED_BODY()
   public:
   	UPROPERTY(EditAnywhere)
   		int32 Foo;
   };
   
   UCLASS()
   class QAGAME_API UCreatedWidget : public UWidget
   {
   	GENERATED_BODY()
   public:
   	UPROPERTY(Category = UI, EditAnywhere)
   		USlateWidgetStyleAsset* Style;
   	UPROPERTY(Category = UI, EditAnywhere, Instanced)
   		TArray<UInstancedBase*> BaseInstances;
   	UPROPERTY(Category = UI, EditAnywhere, Instanced)
   		UInstancedBase* SingleInstance;	
   };
   

4. Compile, create a new widget blueprint
5. Add an instance of 'Created Widget' to the widget blueprint
6. Select it, add a couple of instances under the "UI" section
7. Compile

Result: On compile set values are lost.

(Can also check UDN link for further info on repro.)