Checking AI distance to Player

My enemy AI are confusing the edges of Navmesh for the final player destination. See video link

https://drive.google.com/open?id=1jgz4HCK8sBaCJfCLdbCvPp0CRPENU1iM

How do I get them to double check that they’re actually near the player before dealing damage?

Just before ApplyDamage, use the GetDistanceTo node then compare the number it returns to, say, 100 units (a number). If the number is less than or equal, then the AI is close enough.