A high priced sharpener says that for about a year MK/Wilson sold some high level blades that were not edge-hardened. Your blades are very roughly the "right" era, but I don't remember the details. However, if the problem is new, that doesn't explain anything.
Was the sharpening recent? Corrosion dulls the blades even when not used.
Maybe your ice rink is dirtier than it used to be.
Are you taking care of your blades and storing your skates the same way you used to? Advise which is too hard for most skaters to follow: only walk on the toe picks or in hard guards off ice, and not very far, wipe them totally dry and oil them immediately after each use, before covering the blades in dry Soakers. Never put skates in a bag, box or trunk, and don't leave them in your car.