Meta specifier MustImplement does not list eligible blueprints that have not been opened/loaded

Using the meta specifier MustImplement will cause the associated dropdown to only list classes/blueprints that implement the provided interface. If a blueprint has not been opened/loaded in the editor it does not appear in the dropdown selection

Ex: right click & Create Child Blueprint class

Workaround:
Opening the blueprint or right clicking on it will add it to the dropdown

Regression
No, same behavior occurs in 4.16.3

1. Open UE4 Editor (any project)
2. Add code classes based on ActorComponent (MyActorComp)
3. Add the following to MyActorComp.h

   	UPROPERTY(EditAnywhere, meta = (MustImplement = "MyInterface"))
   		TSubclassOf<AActor> UsingMustImplement;
   

4. Right click in Solution Explorer on the folder "ProjectName/Source/ProjectName" and select Add->New Item
5. Create a Header File called MyInterface
6. Add the following to MyInterface.h

   #include "MyInterface.generated.h"
   
   UINTERFACE(Blueprintable)
   class UMyInterface : public UInterface
   {
   	GENERATED_BODY()
   };
   
   class IMyInterface
   {
   	GENERATED_BODY()
   
   public:
   	/** React to a trigger volume activating this object. Return true if the reaction succeeds. */
   	UFUNCTION(BlueprintCallable, BlueprintImplementableEvent, Category = "Trigger Reaction")
   		bool ReactToTrigger() const;
   };
   

7. Compile
8. In the editor, create a blueprint based on Actor (ParentBP)
9. In the class settings, add MyInterface as an interface
10. In the content browser right click on the blueprint to create a child blueprint (ChildBP)
11. Add an empty actor to the viewport
12. Add MyActorComp to the empty actor
13. Save everything and restart the editor
14. Select MyActorComp on the empty actor and expand the Using Must Implement dropdwon

Result:
ParentBP will show up in the dropdown list but ChildBP doesn't. Opening ChildBP or right clicking on it will cause it to show in the list

Expected:
Blueprints with the given interface appear in the dropdown by default.