hi Arcimboldo! don't worry, I have the same problem with my characters. have you tried not using the behaviour, but instead coding the keys themselves? here's an example of how i make my characters move-
on (key) clicked > (character) move 5 pixels at angle (direction you want the character to move) .
you could use this to make one of the characters move with the wsad keys, and make the other character move using the 8 direction behaviour.
really hope this helps!