This really stretches the limits of what the word "record" means. When you "break a record", it's in terms of performance during a specific kind of procedure, game, whatever.

This is a matter of changing the procedure itself. It's a new convention, or maybe even what you could call a "paradigm shift" within the domain of matrix multiplication, but calling it a "math record" is utterly weird. Breaking a "math record" would be like, I don't know, greatest number of problems solved in your local high school mathletes competition or something.