What is the fatwa regarding a Friday Imam leading prayers in two different mosques on the same Friday?

If the Imam prays a supererogatory prayer in the second mosque as a follower (ma'mum), his prayer is valid and counts as a supererogatory prayer for him. The first prayer he led is his obligatory one. Al-Nawawi stated that the first prayer is the obligatory one based on the Prophet's (peace be upon him) saying: "Verily, it (meaning the second) is a supererogatory prayer for both of you." He should intend the repeated prayer without explicitly intending it as an obligatory one.

However, if he leads the prayer again, this prayer of his is supererogatory. According to the majority of scholars, it is not permissible to follow him because it is not permissible for someone praying an obligatory prayer to follow someone praying a supererogatory prayer. As for the Shafi'is, it is permissible for someone praying an obligatory prayer to follow someone praying a supererogatory prayer, provided that the number of forty is complete without this Imam. This Imam has involved people in a scholarly disagreement and exposed them to the invalidity of their prayers according to the majority of scholars.