Just a die event. They used to grade these at PCGS, but realized they were too common to be worth a premium. It was a cash cow or the finders/sellers and the grading service. But the cow dried up when they were determined to be not a valuable as they originally thought. The people who bought them are not stuck with them hoping they cow starts giving mild again. Then they will sell. Some things are a fad, but fads fade, with an 'e' added to them. That's why I stick with varieties. At least they are stable. What is hot one day may not be as time goes by.