2D Socket issue

In my 2D Blueprint Project, I add Sockets in the Sprite Frames and made Character Flipbooks.

Image 001.png
However, the ReturnValue of DoesSocketExist shows False whether I run it in the engine or packaged game. (The WeaponFX is a FlipbookVariable.)

I actually could get correct world-space location when I run the game in the engine, but when the project was packaged, the ReturnValue of the GetSocketLocation issue appears as below (the text in yellow):

If break the vector to float, the value was 0.0

I wonder if this is a bug come with the current version (4.6.1) or something wrong with my Blueprints?