The ruling on one who knows that his imam has done something that invalidates the prayer

The question: A brother asks, saying: If a person sees that his imam has omitted something in his prayer, or perhaps the prayer has become invalid, should he leave him and separate from him to pray with others, or pray alone? For example, if he omits something in the pillars of prostration, or in the recitation, or something similar?
The answer: If a person prays with someone and it becomes apparent that he has done something that invalidates the prayer, he should leave him and pray with another congregation if one is available; otherwise, he should pray alone, provided he is certain and knows that the imam did something that invalidates the prayer. However, if he is not certain of this, he should complete the prayer and inform the imam or guide him to any matter he may have neglected that does not invalidate the prayer. As for cutting off the prayer without seeing something clear that invalidates it, this is not permissible for him. Rather, it is obligatory for him to complete the prayer. But if he sees a defect that does not invalidate the prayer, he should point it out if he is able, and advise and teach his brother what benefits him.
However, if he sees something clear that invalidates the prayer, such as seeing his awrah exposed, or speaking intentionally in the prayer, like one who is mocking, or one who is laughing and is not forgetful, but rather it appears that he is playing in the prayer, or laughing in the prayer, or something similar to that which is evidence that he is playing and that he is not praying.
The point is: When something appears from him that invalidates the prayer, he should cut it off and pray with others if he finds someone; otherwise, he should pray alone, along with forbidding the evil and teaching him, as is required by the obligation to forbid evil and to teach him what may be hidden from him if he is ignorant. Yes.
The presenter: May Allah reward you.