Is “Back to Back” Summon Luck Real or Just Hype?

I keep seeing people talking about “Back to Back” summons and posting videos where they pull 2–3 legendaries in 100 ancient summons.

Meanwhile, I’m at 160 summons with 0 legendaries.

Is this “Back to Back” thing actually official, or just something players say when they get lucky? At this point I’m wondering if it’s even possible or if I’m just insanely unlucky