You can go above 14 life, assuming you did have the jungo bonus active (which you may not have if you had a split deck), you most likely either beat one of the 2 vortex cards with Stop bonus, or even more likely, you beat a c-wing.
Beating c-wing causes you to lose 2 life and effectively cancels the jungo bonus
You do star with 14 life but you can go over that. Chances are the bonus was cancled by a stopp opp: bonus card or you beat a card which removes your life points or you only had 1 jungo so the bonus didn't work.
If it happenes again at its not due to any of these reasons send a bug report.