Does the prayer of the one being led become void if he deliberately delays behind his Imam in bowing (rukūʿ) or prostrating (sujūd), such that the Imam rises from the posture before the one being led has achieved tranquility in it?

The prayer is not invalidated if the congregant intentionally lags behind the Imam in bowing or prostrating, even if the Imam rises before the congregant achieves full composure. However, it is invalidated by intentionally lagging behind by a complete pillar, such as when the Imam rises from bowing or prostrating before the congregant even begins them. If the congregant does this without a valid excuse, their prayer is invalidated.