I encountered a probable bug when retrieving a target actor from the blackboard, i found i was setting the blackboard actor correctly but when retrieved it gave me the controlled pawn instead of the target pawn (they are the same class, i am setting a unit to attack another unit of the same type).
I have managed to fix the bug by retrieving the blackboard through making a literal name for the key selector rather than using a key selector variable in my Task. The previous method worked as expected when attacking an actor of a different class (resource node). I feel like the two methods should produce the same result, however i may be misunderstanding or mis applying the method due to lack of experience.
Hopefully the image below clarifies the situation
Top line shows current implementation that works as expected, disconnected variable there to illustrate previous method that causes unit to damage itself.