There is something seriously wrong with this attack. Do you know what it is?

Ma Ji's "Close Combat", Meng Su's "Seven-Step Press", and Lin Chong's "Continuous Kicks" are shown here. Can you tell where these techniques are? Yang Kun's "Gripping Techniques" manifested in "Double Fists", however, are wrongly applied. Many martial artists use the double-fist attack in this way, but do you know what serious faults is contained in this double-fist attack?