Huh? The point is it had no precedent before (and has none since). Who knows how long the return period is for such an occurrence? We don’t know because we only have ~75 years of solid data.
Strong Niños occurring within 3 years of each other is easily within the limits of ocean-atmosphere physics. We know they’ve occurred 4 years apart, mere decades ago. Two events occurring 3 years apart would have a longer return period, but I’ll wager you it has occurred dozens of times over the last millennium.
Theoretically any of this stuff in the warm sector could be spinning tomorrow. Fast storm motions too. LOT could have their work cut out for them, potentially dealing with quite a few troublemakers simultaneously.