Does swallowing blood from the nose (epistaxis) involuntarily, and then voluntarily after becoming aware of the fatwa, invalidate the fast?

"The obligation was not to swallow any of the blood, even if it meant staining the clothes, because purifying clothes is easy and a small amount of blood is overlooked. However, since you deliberately swallowed the blood until it entered your stomach, intending to prevent it from staining your clothes, your fast has been invalidated by that. You are required to make up that day if the fast was obligatory."