Gameplay Debugger selection selects the AI closest to camera focus, not to where mouse points, sorry. Addressing this is somewhere on our ToDo list, but not very high (so many more important things needs doing first!). A way around is, that I’m using on a regular basis, is structuring your game/AI so that it can run in Simulation mode in the editor. In simulation mode Gameplay Debugger will draw data for “selected” pawn, meaning the pawn picked from the level or from scene outline list.
Cheers,
–mieszko