I'm sure these cleats have been on my daughter's riding shoes since the day we bought them. She has used them for years now and I only noticed the odd design tonight when it prevented her from clipping into some Performance Campus pedals. She wore these same shoes yesterday with some actual Shimano pedals on her road bike, and they worked just fine. I did an image search for "SPD cleat" and didn't see any that looked like these do, with the extra metal tabs molded into the back of the cleat. Has anyone seen these before and know what they are meant for?
The unusual one is on the left, with a normal one on the right for comparison.