CommentStreams:50fbee115cbe911c4c0cb8214e969817

I think you are talking about EnchantingSong {n}, which is the effect used by the artifacts. That effect actually hasn't changed. The EnchantingSong effect used by cards (Ambassador, Royal Musician, Miss June), as well as by the WisdomTome artifact has been improved from -20% ATT to -30% ATT as mentioned in the table above. This is a rather uncommon case where built-in effect is stronger than the level 5 artifact effect (typically built-ins are set to level 4). They must have been aiming to improve the WisdomTome power of their arcane Elven Queen card.