Mine work fine. Those blades on fit the cutters with the round hole. Not the Ofla ones with the weird center.
As with anything one will get "duds" once in a while, I have had the same issues with the expensive ones. For all we know they could be from the same manufacturer. Different packaging, same product.
My husband sees this in his power tools....
Dewalt is Black and Decker with a yellow casing.
Porter Cable, Rigid, Black and Decker, Dewalt, Craftsman, Hitachi are manufactured in Asia at the same factory just different colored housings.
The company is know known as Stanley/Black and Decker.