Yep, ref was at fault there. And Khan should have being stopped after that first KD against Prescott, he was all over the place. Like you say, if that was a foreign fighter there's no doubt the ref would have waved it off.
He says stop punching ? Poor from the referee as well though, really should of got in between them or called break instead of stop punching. You see Refs give a warning without breaking like no hitting behind the head but that had no real warning to anyone just stop punching