Does the prayer of one who intentionally lags behind the imam by a pillar become invalid?

The questioner:
May Allah reward you, Honorable Shaykh. This questioner says: If a person prostrates and prolongs his prostration, and then the imam rises from prostration and sits.

The Shaykh:
Yes.

The questioner:
He says: If a person prostrates and prolongs his prostration, and then his imam rises from prostration and sits between the two prostrations, and then the follower stands up after that, and his imam has already prostrated the second prostration, does this rak'ah become invalid? Because we have heard that some imams do not say it is invalid unless one lags behind the imam by two pillars.

The Shaykh:
If he intentionally lags behind, if he intentionally lags behind until the imam enters the second pillar, he lags behind the imam by a pillar until the imam enters the second pillar intentionally, his prayer becomes invalid. The saying of the Messenger (peace and blessings be upon him): "The imam is made to be followed," meaning to be imitated, so do not differ with him. But if he did not intend this, because he was sleeping, dozing, or did not hear the imam, did not hear the takbir, and then he stood up and performed the sitting between the two prostrations, and then caught up with the imam in the second prostration, there is no harm, because he made up what he missed and he is excused, because he lagged behind him unintentionally.