In normal circumstances, I think it would be. Until you move in and live somewhere and start using things, you cannot detect the problems. I think it is totally unreasonable not to let the purchaser see their apartment BEFORE completion though, which I understand to be the case at Green Hills.! 😯
I think it advisable to thoroughly snag the property before completion (we once found over 40 minor and major faults including missing specifications), delay completion until rectified, or, as Drakan says keep a large retention of funds back until they put right.