Why my Engine crashes when I do this?

Hello!

So I’m working on a bigger project. I created an Initialize custom function in c++ for a widget. I made that BlueprintCallable. In bp I override the On Initialized function and then call my Initialize function. When I want to do this, it crashes, but when I add a 0.0sec delay before calling my Initialize function it works, but If I change something in c++ (I’m not sure if its doing this time, but it doing it sometimes after build) and build It crashes with the delay. If I set the delay to 0.1sec it works and If I set back to 0.0sec It works again, until the build which screw up the things again.

Anybody know why is that?