Apparently there have been some production issues with the album, and as a result, he had to cancel all of the preorders people had made. He asked for continued patience and apologized for the inconvenience. His tweet didn't state what was specifically wrong with the album, but some of the promo material did misspell one of the songs as "Fairy Times Momery."
"突然の発表になりますが8月31日発売のリマスタリングBEST ALBUM「BEST COLLECTION 2004~2008」は当方のミスにより発売中止になりました。 予約いただいている方には追ってメールを送らせて頂きます。急な発表でご迷惑をおかけしまして申し訳ありません。ご了承お願い致します。"
This is kind of a bummer, as it was due to be released on an anniversary of the band's (first) breakup. No new release dates have been shared yet, but I am sure the album will be released eventually.