Mobs not being hostile

I'm having a problem with the mob AI builder, where my mobs are not attacking me if I get near them.  I know that this topic has been covered before, but all the topics I've found are either unsuffciently answered or outdated.  I have tried the "attack in sight of type entityPlayer" (with and without check marks) and the "attack targets (make mob hostile) call for help" task.  I don't want to use an AI base, as that changes the mob drops (for some reason) so I would like to know if this is a bug or if I am just being stupid.  Thanks!