Do the rulings on voluntary fasting, including the consequences of breaking such a fast, apply to making up a day from Ramadan, or do they only apply to the fasting of the month of Ramadan?

What has been mentioned applies to the fasting of Ramadan, its making up, and supererogatory fasting. So, whoever doubts the invalidation of their fast by swallowing something that breaks it, their fast is valid, whether it is supererogatory, obligatory, in Ramadan, or a make-up fast, or otherwise.