What should I do if I enter a mosque to perform the Friday prayer and it becomes clear that it delivers only one sermon? Should I leave the mosque and pray Dhuhr, and would I be sinful if I intentionally went to this mosque knowing that it sometimes delivers only one sermon?

The jurists agree on the obligation of the Friday sermon for the validity of the prayer. The majority of scholars hold that two sermons are obligatory for it, which is established from the Prophet (peace be upon him) and was practiced by the Rightly Guided Caliphs. This is a condition for the validity of the Friday prayer. If the Friday prayer is performed with only one sermon, the prayer is invalid and must be repeated as a Dhuhr prayer. If you find a mosque that performs the prayer with one sermon, it is better to seek another mosque that performs it with two sermons. If you are unable to do so, pray with the first Imam, and you are not required to repeat the prayer because there is a considerable difference of opinion on the matter, along with advising the Imam to establish the prayer according to the Sunnah.