Not that I could do any better.....

But that Aeromexico flight was transporting Oingo Boingo on their World Tour.

I was just wondering that myself. To take such large airframes and unsettle them that much(even with PIO), something has to be changing quickly.

Anyone experience it? Been there, done that, obviously survive it?

I've seen the KAL before, and it still looks like PIO, just laterally this time. There may be a bit of wind involved, but it's still excessive and out of phase responses by the pilot that drives the oscillation.