Thresh AA's + Attack speed

For fun I decided to play ADC Thresh in Bot lane a few games and I noticed that regardless of what your attack speed is the animation for Thresh causes very slow AA's when moving between attacks. It's almost like the animation isn't sped up at all (unlike other champs) if you're moving between the attacks. You only see the increased attack speed when standing still.

Is this intended behavior? I feel like his attack animations should be increased in speed corresponding to his attack speed bonuses from items like Static Shiv. Otherwise in fights you're forced to stand still AA'ing or you get off half as many (exaggeration) AA's as the enemy adc with the same AS.