What should a person who joined the prayer late do, if the imam made a mistake and said the tasleem after the third rak‘ah of a four-rak‘ah prayer, then remembered and stood up to do a fourth rak‘ah?

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Check below answers in case you are looking for other related questions:
Not doing sujood al-sahw in order to ward off waswaas (insinuating whispers from the Shaytaan)
Should one who joined the prayer late repeat the prostration of forgetfulness if he did it with the imam?

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Related Answers:
Their imam forgot a prostration then he repeated the rak’ah, but some of them did not repeat it
He started to pray, then he wasn’t sure whether he formed the intention to pray or not; does he have to repeat it?
Distraction during salaat (prayer) by shaitan
Not doing sujood al-sahw in order to ward off waswaas (insinuating whispers from the Shaytaan)
Should one who joined the prayer late repeat the prostration of forgetfulness if he did it with the imam?

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