From clips I've seen, it's usually at the foot of the bridge on the performance corridor side of the Pixar Pier bridge.
I've also seen clips of it on the stage at Pixar Pier (near the games). This is also where the app is showing it.
Finally, it looks like it may have taken place in San Fransokyo on occasion.
So, if you're seeking it out, I'd ask at an information table on the day you want to see it.