Compiler error on startup within a ForEachLoop node

When I open the editor I have to delete the add unique node then drag off the for each loop and attach it to the targettable monsters. And everything compiles correctly.

The attackable area node is a capsule component, the targettable monster variable is an array of character objects.
This blueprint is being run in the Player Blueprint. What the code is trying to do is grab any monsters in range and compile them into an array so that the player can choose which monster to attack.

Should I worry about the compiler error, or will it fix itself when I package the game.

The error the editor is throwing