Charitably, you could read this as "its overall intelligence [is in a class that] ranks second only to [that of]..."

Yeah, bad wording it seems. Though a charitable interpretation is that Fable 5 and GPT 5.6 Sol are joint 1st place in the measurement.

While you are technically correct, in English it’s perfectly fine to say it this way as well.

“Second only” here has meaning “next after”, not “number two”.

Not if the others tie for first place.

Which is still great because it means neither of the two best financed labs in the world manage to produce even two models themselves that would beat Kimi K3.