Consider the fasting example side by side.
ʿIbārah: nighttime intimacy is permitted and fasting is to be completed until night.
Ishārah: a permitted late-night act may leave someone requiring ghusl at dawn, so that state by itself cannot invalidate the fast.
The first ruling reflects the prominent communicative purpose. The second follows from the time structure of that ruling. The distinction is not the ordinary difference between an easy and a difficult meaning, but between the purpose of the passage and an implication of its wording.