According to Toby, the server's owner, Cloudflare turned off their proxy, letting all attack traffic hit the origin.
Given the server's public is mostly teenagers, I doubt TubNet will release any technical post. However, it would be nice to see Cloudflare's side here.
Ugh, HN removed the timing param in the post: https://youtu.be/FoI4GPWxRtA?t=467