Watch it again. If that was planned then it was executed poorly. The landing gear takes a pretty good impact, and on recovery there is a bit of PIO, which likely stands for "Pants Infiltrated with Odor."
I think it was intentional. He had a good position established and then he fell out of formation a good 20 ft to touch the water. Yeah, he porpoised a bit after but it was still intentional to touch.