casting actor to character

Hi,
So I must be not understanding something about castings. Unreal hangs for me when loading at 72%. Through shelving files on p4, and testing I’ve narrowed it down to casting from a hit actor to my NPC class which is a subclass of Character.

What is happening is, for example, my player has a knife. The knife has a collision box over the blade. When the box overlaps with my NPC’s the knife sends point damage. All was working great. I added a “cast to NPCclass” to cast the hit actor into my custom NPC class. When I make that cast everything works great until I close Unreal. Then it won’t open and I have to revert the file.

Has anyone experienced something like this and maybe have an idea on what I could do to fix it? My current plan is to just make an interface and use that, but there are more people than just myself and I would hate for anyone else to have to revert work because of this.

Russ
UE 4.11