Mispronouncing Obligatory Surahs In Salah
I think if you did in past unintentionally then Allah is Raheem, inshallah he will accept your ibadat. Ask for his forgiveness. Now when you realize about your mistakes, then try to fix them inshallah . Prophet Muhammad SAW told to do istighfar right after finishing Salah. To ask forgiveness of any mistakes during Salah, intentional or unintentional.