They were probably filmed while falling at terminal velocity.
Since heavier objects have a higher terminal velocity and the two ladders have the same weight, they have the same speed in the beginning.
But as the left latter hits the table, it gets lighter, while still carrying the higher momentum, and thus falls faster than right one.
I’m not a physicist, just a 24 year old dude from Germany who likes physics; but, with my limited knowledge, I think that this is the most plausible answer.
But only if they were falling at terminal velocity of course, otherwise I do not know.