The spellblade weapon property from Player's Guide to FaerunPlayer's Guide to Faerûn makes you immune to a single targeted spell. This part of the description
When the wielder is next subjected to the chosen spell, the weapon absorbs it.
got a somewhat ambiguous translation in italianItalian.
quando colui che impugna la lama è soggetto a tale incantesimo per la prima volta, l'arma lo assorbe
This translates back into englishEnglish as
When the wielder is subjected to the chosen spell for the first time, the weapon absorbs it.
Problem is, I'm not sure how to interpret that "next" so to me the englishEnglish version is not clarifying either, maybe someone more knowledgeable of the englishEnglish language might help me understand.
I have found one post on a forum http://www.giantitp.com/forums/showthread.php?507075-Spellblade-Enchantmentone post on a forum where this is discussed, but it was not very convincing, even though iI lean towards the permanent use since otherwise it would've specified what happens once the spell has been abosrbedabsorbed the first time (usually on items with limited uses it says something like "after all the charges have been used etc...etc...") and on top of that it'd be a pretty unique weapon property, iI don't recall any standard weapon property that disappears after the first time it's activated.