Not sure if this is a bug or not....

If I recall, it was a few weeks ago and I was looking at The Moody Blues discography. Their KEY albums at that point were "Days of Future Passed", "On the Threshold of a Dream", "To Our Children's Children's Children" and the complilation "This is The Moody Blues". The next day I looked at the very same discography and noticed that "Days" and the compilation's ratings dropped. "Threshold" and "Children's" were no longer key albums, and had dropped dramatically in rating. The number of ratings for each album were exactly the same as the previous day. Later that day both of those albums were back at the KEY status and had the same rating as the day before. The same applied to Catapilla's discography, but later that next day the ratings were back to what they originally were the pervious day. It appears that the same thing has happened again today, at least to The Moodies page. The number of ratings is the same, but most of the albums have dropped in rating. Can someone explain these erratic rating changes?

Alright, thank you for the explanation.