Is it obligatory to re-fast four consecutive months with a single intention (fasting a vow and making up for Ramadan) after learning that the intention for each must be specified separately?

Votive fasting and making up for missed Ramadan fasts are different, and the intention for each must be specified individually due to their differing natures. If the nature differs, specification is obligatory, and the need for certainty when there is overlap is also obligatory. Therefore, if a person intends to fast but does not specify the intention for making up a missed fast or fulfilling a vow, their fast is considered supererogatory and does not suffice for either making up a missed fast or fulfilling a vow.