He had the kite pumped up hard as a rock, I made sure to triple check that before his second and third outing.
After watching him get pissed the first time, I had to look at his stuff. It seemed "normal" to me.
I have seen this rider struggle now on several occasions get so mad he was yelling. The first time I saw him get mad was a few months ago at the SW. The last time was last week at EB.

Do you think the rider just doesn't know how to water relaunch kites?

You are right about one thing, I would definitely like to see Dave relaunch it during a demo.
It's a total mystery to me right now how that thing appears to stay pegged to the water.
I would like to demo the kite. I just want to be in shallow (walk back) water, if necessary.