Here in fact is what might have happened:
"A jump-off can occur when there is a tie, as was the case on Sunday night. It results in the bar being lowered to the previous height both jumpers cleared. Each athlete gets one jump, and the bar is alternately lowered and raised to a different height each time until the first person fails to clear the bar."
But, the rules now state that athletes can pass on a jump-off.
I really don't understand the hullabaloo about this: both from the pro and the anti. It seems, as I've said several times, now, a perfectly fair outcome. Joint first gets you first place, fair enough Neither though do I see how "sportsmanship" comes into it.
I think it's cool that they did it though.