I've been looking at your post. It indeed looks like a mistake.
The coin on the Numista link looks like a 1/4. Little space for inscriptions on the obverse between edge and circle, and the date fits the quarter in the WC.
I would suggest you ask for a modification of the page on Numista and then create a new one for the real 1/2.
Hope someone looks at your post ??
Cheers,
André
Quand l'Histoire et la Géographie se croisent sur nos pièces de monnaie ...