I think that's only from Hyeang's timeline, because she made that ill fated link with ML, the strings of fate became so tangled they suffered a lot. But when Queen Mother cut off that tangled fate, heaven made new strings of fate, so their fate is a new one and not tangled like previously. So basically they successfully made each other fated partner by letting fate run its own course, opposed to what happened in thousand of years ago

Because hyeang stole a fate that wasn't hers like in the way that the heavens didn't assign her as daeryeos fated partner, implying that he had an assigned fated partner, what would happen to them