What is the ruling if the Imam precedes the follower by a complete essential pillar (e.g., bows and rises before the follower bows)?
Chapter on the Description of Prayer
Al-Mughni
Book of Prayer
Primary text
If the Imam precedes the follower by an entire pillar, such as bowing and rising before the follower bows, due to a valid excuse like drowsiness, crowding, or the Imam's haste, the follower performs the action that the Imam completed and catches up with the Imam. There is no consequence for the follower. This ruling is explicitly stated by Ahmad. This is generally not disputed when the Imam completes a single prostration before the follower, in which case the follower follows him upon the Imam's raising.
Supporting text
If the Imam precedes the follower by an entire rak'ah or more, the follower follows the Imam and makes up what the Imam preceded him in. If the follower misses two prostrations, that rak'ah is not counted. If the precedence is less than a full pillar, the follower performs the missed action and catches up with the Imam. Scholars maintain that if one is prevented from prostrating due to crowding on Friday, they wait until the crowding subsides, prostrate, and follow the Imam, unless they fear missing the bowing in the second rak'ah with the Imam. This implies performing what was missed even if it exceeds one pillar.