Or, perhaps KoL itself really did have the bogus plural for this item and both KoLmafia and the Wiki correctly recorded it.
Then, after somebody made a bug report and several years later KoL decided to fix its bug, now both KoLmafia and the Wiki are incorrect.
I am fairly certain that none of us here are dumb enough to simply copy things from the Wiki, which is known to be full of bad information, without checking on it.
I sure wish we had a category for "KoL change". I guess I will just change this to "New Content".
Thanks for the report.