Hello OhiraKyou,
After looking over your project I found that your issue may be due to circular references. I have provided a picture with an example of one that exists within your project. The types of issues caused by circular references are consistent with the types of issues describe here. If the information being passed in unrelated ( not dependent on one another) then it is a known issue (UE-11470), however if the information being passed is dependent on the information needed (circular dependency) then you will need to find a way to rewrite the logic so that it breaks the circular dependency. I hope that this helps.
Reference viewer of your project:
Make it a great day