If the mental states affect perceptual judgment, then the perceiver observes the world as it is but jumps to a particular conclusion that's in line with their mental states. If the mental states affect the perceptual experience, then they do not observe the states as they actually are but see the world itself in a way that aligns with their mental states and make the subsequent (reasonable) judgments about these incorrect perceptions.
The former seems to be the fault of the lacking reasoning faculties of the perceiver, while the latter is almost beyond their control, in that it's a defect of human cognition that is unavoidable and insidious.