Is it permissible to pray with the Zaydis in Yemen if their Adhan for 'Isha prayer precedes that of the Sunnis by approximately fifteen minutes?

If the prayer is established in these mosques before the time for the 'Isha prayer, which is considered Islamically valid by the Sunnis, then it is not permissible to pray with them because the prayer is not valid before its time, and it is considered void. However, if the prayer is delayed until the time for 'Isha enters, then the prayer is not invalidated by calling the adhān before the time. One should seek a congregation with whom one feels comfortable praying.