Theres a bug in the Itemstats function of the forum and I believe its due to Allakhazam changing how you search the database they have without of course telling anyone they were changing stuff up. Because of this, some items work, some dont via name. If you use the item ID off the site, it works every time but the lookup by name seems to be problematic and only on some items.
Im working on the issue and trying to resolve it as the original author of the addon is in denial of there being a problem.
Fixed. ;D