Most of the "flat 3s" I've been seeing lately are just backflips thrown a little over the shoulder.
Correct me if I'm wrong but this is not a flat 3:
https://www.newschoolers.com/videos/watch/777277/Flat-3
2:38, this is a flat 3
https://www.newschoolers.com/videos/watch/777278/Pep-Fujas-2010-self-edit
In my opinion they look nothing alike. Why are weirdly thrown backflips confused so much with flat 3s? I don't get it.