Prayer: If One of Several Ghusls in Ramadan Was Invalid, What’s the Ruling on My Prayers and Fast?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: If One of Several Ghusls in Ramadan Was Invalid, What’s the Ruling on My Prayers and Fast?

English:

Question #526:

If a person performs janābah ghusl three times in the month of Ramadan, say for example, on the twentieth, twenty-fifth and twenty-seventh of the month, and afterwards becomes certain that one of these ghusls was incorrect, what is the ruling with respect to his prayers and his fast?

Answer #526:

His fast is correct, but it is based on caution that he must perform the qaḍā’ of some prayers so that one becomes certain that he has discharged his obligations.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer