Do the prayers that were performed have to be repeated if a fluid was discharged after ghusl—the nature of which was not ascertained to be semen—taking into consideration the opinion of scholars whose madhhab is not followed, and without changing clothes?

There is a difference of opinion regarding the necessity of ghusl (definition) for someone from whom semen is discharged after having performed ghusl, and a person may adopt one of the recognized views. If a person is unsure about the nature of the fluid, there are several scenarios: either it is more likely to be semen, in which case there is a difference of opinion regarding the necessity of ghusl; or it is certain to be madhi, in which case washing the affected area and sprinkling water on the garment is sufficient, and prayer performed with ritually impure clothing due to ignorance of the impurity is valid. Or, if the person is ignorant of the fluid's nature, they may choose between considering it semen, in which case they perform ghusl and repeat the prayers, or madhi, in which case Shafi'is are obligated to repeat the prayers if the garment was impure with madhi.