Is this boat new to you? If not, was it always like this or did this just start? What was happening just before this started?
Sounds like a loose rocker in that video, which obviously is not your video since it was posted in 2012, and they followed up with a resolution. In my opinion the resolution posted in the description did not fit the symptoms to me, of a loose rocker. They R&R'd the heads which would have mandated resetting the valve lash anyway, not sure how they proved the water in the cylinders swapping places theory. Stranger things I guess.
