Trying to reference an unowned pin

I have a C++ project. Every time I compile it there’s no problem. Whenever I run the UE Editor, there’s no problem. Whenever I play the game in viewport or new window (PIE), there’s no problem. Everything went very well. The problem begin when I tried to launch in debug game editor mode from VS. It always shows error, telling me to either break the operation or continue. Here’s the screen shot:

Previously, I’ve compiled and launched in debug game mode hundreds of times and never encountered such error. But it happen just recently. The weird thing is that if I press “continue”, then the UE Editor can still launch normally. I can use the editor perfectly and even play the game perfectly in accordance to my code + blueprint. The breakpoints, I put in my code in VS, also function normally, when I enter that stage of the process.

So the question is, what could possible cause this unexpected error and how could I resolve it?

Or is it a known bug?