Hughton is a diplomat, Kayal doesn't want to be seen as a whiner, the ref didn't say anything - we know he made an error with the goal, if he then admits to missing other key incidents he is going to be in a bit of trouble, so it's easy to see why he would claim retrospectively (helped by...
Looks to me like Kayal lifts his leg up to block Barton, as Barton is coming down he looks and sees the leg under him and doesn't readjust. I don't think he had planned to stamp on Kayal's leg when he jumped, but as he was coming down realised he would and did nothing to avoid it. I'd say that...