Those were from the 1st UFC if thats what your thinking of, and it was because Shamrock tapped, and he released the hold, but the ref didnt see it and almost allowed the fight to go on (Shamrock admitted he tapped, but the ref still said he didnt see it). So the next few fights he fought in UFC, he held the subs extra long to make sure the ref saw...

At least thats his excuse.