Topic: Eating Suhoor 1 minute After the Time for the End of Suhoor Written on the Prayer Timings Chart    (No-13320)

In our mosque the alarm for the end of suhoor rang at 4.39 am today, and after ringing for a while, it stopped and the azan was called. When we checked the time for subah sadiq on the prayer timings chart, we found out that the time for subah sadiq was at 4.38 am, which meant that the alarm rang one minute later than it should have. Later, we checked the masjid clock, the clock was one minute slow.
What do the honorable muftis say about this whole situation?
Will the People from our apartment who kept eating until the alarm rang have to perform qaza for their fast? Or is there some room for error because they didnt know that the alarm rang a minute later than it should have?
Though, we have now fixed the masjid clock's time Alhumdulillah, we do not know for how long the clock's time has been wrong. Keeping this whole situation in mind, please guide us.

As a precautionary move, suhoor should be completed 3-4 minutes before the time for subah sadiq (the break of dawn) that is written on authentic prayer timing charts. However, since these calculations are estimates and the times of different clock's are mostly different, if someone has carried on eating one minute after the time for subah sadiq, their fast remains valid and there is no need for qaza. That being said, it is necessary to act cautiously in the future.

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دلائل:

رد المحتار: (371/2، ط: دار الفکر)
(قوله: وهو اليوم) أي اليوم الشرعي من طلوع الفجر إلى الغروب، وهل المراد أول زمان الطلوع أو انتشار الضوء؟ فيه خلاف كالخلاف في الصلاة والأول أحوط والثاني أوسع كما قال الحلواني كما في المحيط.

Allah the Almighty knows best.
Darul ifta Al-Ikhlas, Karachi.