Diablo 2: Resurrected players have been wasting endgame items thanks to a typo from developed Blizzard in the official patch notes.
In Diablo 2, runes are one socketable item you can use to improve your gear in the endgame with various bonuses. But if you install runes in a particular order on a particular item, you get a unique piece of gear called a Runeword. Those items are some of the most powerful gear in the game, but they're fiddly - if you make a mistake slotting the runes into your gear, you must destroy them all to make it right.
New Runewords are often added in patches, and Blizzard spells out the rune order required to activate these new items. But in the Season 3 update, one Runeword in the patch notes showed the wrong rune order, and this typo has had players wasting their runes in pursuit of an item that's ultimately useless.
It seems the issue stems from some changes made as part of the PTR testing cycle. The Mosaic Runeword originally called for a Mal+Gul+Thul combo, but players weren't in love with the cold damage provided by Thul. So Mosaic became Mal+Gul+Amn, with Amn providing life steal instead.
Based on community discussion, it seems the patch notes were originally published with the correct Mal+Gul+Amn combo, but at some point, a revision turned it back to Mal+Gul+Thul. They've now been corrected again, but the end result is that there was about a day where Blizzard's mistake was happily encouraging players to waste their runes on a non-existent Runeword.
It's not a new Diablo 2: Resurrected season without some issues - remember when Season 2 was delayed because Blizzard "didn't plan very well"?
