Wing flutter & Hydrofoils flutter

Mahalo,
I was just watching the the US nationals regatta in Moth class and in this video
https://vimeo.com/136467586
at the 04:30 + the whole foil set up come in the flutter
OR
maybe I am wrong and this is just the sampling of the video
(hope yes) otherwise I can only imagine the sound and the vibration :-(

We all know how hard are the Moth foils build, almost unbreakable and
to see the flutter like this O la la! I hope everything was gong well there!

I know flutter is not common on Mach2 boats, here I can not judge if this foils are "home build"
but it is interesting to see!

My answer to this problem are Y foils!

dr.Lojz