I think the "transition duration" of Animator Cross Fade is a percentage of the animation length, not an actual real world time.... I could be wrong.
There are a few actions where the "time" setting seems to be relative measurement, not a game constant. In this case, I think the transition setting is analogous to the transition fade time that you can set within a Mechanim transition. (0.25 would be 1/4 the length of the animation, 0.1 would be 1/10th)... again, I might be wrong.
So in your video, I am assuming the longer setting is blending the jump animation for so long that it is smothering the jump (why he seems to only jump a little, it is being blended with the idle). Try setting it to 0 which is basically no transition time at all and you will see the full jump...