If someone breaks their fast under the assumption that Maghrib time has entered—either based on personal reasoning or reliance on the information provided by a trustworthy source—but it later becomes clear that they did so before sunset, then they are required to make up (qadha) for that day. This is because they broke their fast during the daytime of Ramadan, and the assumption that turned out to be wrong does not exempt them from this obligation. The principle is that daytime remains in effect until there is certainty of sunset.
Thus, a person should exercise due diligence and ensure the time for Maghrib has certainly arrived before breaking their fast. The Adhan broadcast over the radio does not provide definitive knowledge (yaqeen) of the time for Maghrib, as such certainty can only be established through a mass-transmitted (mutawatir) report based on direct sensory observation or by the person observing sunset themselves.
And Allah knows best.
