I had the same problem with a fein supercut, which uses the same mechanism.
I was afraid, that if I lubricated the pin, the blades wouldn't lock properly anymore; so I used a flat screwdriver or the back of another blade to pry it loose for a few weeks... when I finally got so annoyed I sprayed it anyway; problem fixed, and the blades still locked perfectly. (I can't remember if I used wd40 or dry silicone lube, but it worked)