This is aboutn Lupin's potion I think there's a missunderstandnig coz they say that he should take the potion in the week before full moon. But Snape gave him the potion the night of the full moon.

"The potion Profeeser Snape has been making for me is very recent discovery.It makes me safe,you see.As long as i take it in the week Proceeding the full moon."p.352,353.

But when Lupin starts transfering Hermione said:-
"Oh my- He didnt take his potion tonight! He's not safe"

While that night was the night of hte full moon.

Curuios isnt it.
If anyone know any good explanation for this post it here