The rivets are just another type of waterslide decal. As it has been mentioned, I have seem many instances of cracked decal film on older decal sheets. I think that humidity also makes them age fast. This is especially true for decals which use very thing film, (like Microscale), but I have also seen shattered decals which use much thicker clear film (usually in Japanese model kits from Tamiya, Aoshima or Hasegawa).
Applying a coat of Microscale clear decal film over the entire sheet of cracked decal should work. I usually apply at least 2 coats.