Fatal Error happened when I start my packaged project

Look here

his occurs because there exists a circular reference between the nativized parent BP and the non-nativized child BP asset (which is a data-only Blueprint in this case).
Current suggested workaround is to force the child BP to be nativized as well, by adding a dummy variable or component to the ‘ChildBP’ asset.
A crash will still occur with EDL disabled as well, although the callstack/assert will be different.

I would suggest packaging with nativized unticked and see what happens.