No, it probably wasn't an error. Read your own quote above about "before 6am" (pasted below), what am I missing? I don't think CX has any flights before 6am. Thus, no entitlement for second day flight.

From your quote:
"First and Business Class customers connecting on the same day of travel, or before 06:00am the following day"

I don't see where it says anything about 24 hours? It says "same day" and adds the part about up to 6am the next day. It's clearly designed for same day connections (including those which depart after midnight as many do) but not for overnight connections.