Originally Posted by November Rain
Does anyone have an idea when they think he lost it.
I'm going to go with the return of the phantasm. That probably shook him up more than anything else. The first batch of his humanity was removed when andrea first left him, she took out the dregs with her second coming. That was probably when he started being more batman and less bruce wayne.
I agree. When I think of the continuity of the DCAU I like to place Mask of the Phantasm between B:TAS and TNBA. To me it seems a perfect reason for the transition in the tone of Batman.