Is my prayer valid if I pray Fajr behind someone who lisps the letter "R", and then I separate from him and complete my prayer alone?

The validity of the prayer leadership of a lisping person is a point of contention among scholars. The Maliki school and one opinion within the Hanbali school hold that his imamate is valid, because it does not involve altering the meaning, but rather a deficiency in pronouncing letters. However, the majority of scholars are of the view that a lisping person should not lead in prayer those who are not like him. There is no blame upon someone who follows the opinion that deems his imamate valid. According to the opinion of its invalidity, leaving the imam and completing the prayer individually is valid.