Hopefully his map has 1 unit-type of that unit per player, else, the trigger will bugged (not MUI).
Also, you should change the (Owner of (Learning Hero)) to (Triggering player), calls less function, works the same.
Also, (Triggering unit) == (Learning Hero), if you use (Triggering unit), it is faster call than (Learning Hero) because (Triggering unit) is the native response.