I think you mean this: https://arxiv.org/abs/2412.06769

From what I can see, presuming o3 is a progression of o1 and has good level of accountabiltiy bubbling up during 'inference' (i.e. "Thinking about ___") then I'd say it's just using up millions of old-school tokens (the 44 million tokens that are referenced). So not latent thinking per se.