A man briefly, on entering an entirely new office building for the first time, has a strong and striking sense that he has been in this exact place before, though he immediately recognises this can't actually be true, and the feeling passes within moments. What category of disturbance is this?

This is a distortion of recognition (specifically déjà vu, one of its named patterns): the felt sense of familiarity is disturbed — wrongly present here — while the actual content of the experience (a genuinely new building) is accurately perceived, exactly the pattern the phenomenon's own text describes. It is not a distortion of recall, which would involve the content of a remembered event being falsified, not just the accompanying feeling of familiarity. It is not a delusional memory, since he does not hold a fixed false belief about having been there, only a passing feeling. And it is not confabulation, since nothing is being actively fabricated to fill a memory gap.