Originally Posted by CJ82Sky
check his back for soreness - could be that he lands and it causes some discomfort that he's also trying to avoid.
^ This would be my first guess. An ill fitting saddle, or just a simple matter of not being in shape could result from a sore back.
Also, if you hit him in the mouth over the jump, he could just be reacting to the pain.. Some horses just aren't as forgiving as others!
If it is a matter of disobedience, or just a bad habit, I think the pole idea (as suggested already) would be a great idea. Maybe give him 2 strides of canter after the jump (to regain himself) and then add 2 ground poles one stride apart. That should get his attention enough for long enough for YOU to regain yourself, and then you can circle him to get his attention back on you.