They must be using a hell of an accelerant then, 7-day compressive strength on a good pour is 70% of design strength.
I bet someone has screwed the pooch on the slab thickness or used the wrong mix design on the upper floor concrete, like they had lightweight spec’d and the kept using standard going up!
My guess is they would have been spotted any issues on the compression tests(28 days?) before they added six additional floors.
Another guess, a tilesetter (?) is unhappy about leveling up the floors, tells everyone that the decks are way out...
More fake news.