Blueprint Runtime Error

Hi, I’m new to Unreal and received the Blueprint Runtime Error. I am trying to get my zombie to switch between chasing and walking randomly based on if it can see the player. I am using the blackboard key as the boolean to switch between the states. The zombie acts the way I intend it to but I am not sure how to fix the issue.

Resolved. The issue was that there was a tick before event beginplay was being called. I added a delay after isvalid.