The Obsidian Aspectral Earthstone is an item that is tied to Dragonflight Season 2 Hero achievement, however Mythic Sarkareth kills still gave this achievement post Season 2 of Dragonflight to 11.0.2 until 11.0.5 caused it to no longer provide the item.
The Season 1 Dragonflight item Gleaming Incarnate Thunderstone is still obtainable with Mythic Raszageth kills, however it is rewarded from Deep Cuts From the Vault achievement which is under Collections → Appearances.
Furthermore The War Within Season 1 has its own item Luminous Nerubian Catalyst Stone from Web-Wrapped in the Finest Silks which is under Collections → Appearances and following Dragonflight Season 1’s item’s logic it should be available after Season 1 has passed with a Mythic Queen Ansurek kill in future seasons.
So is Obsidian Aspectral Earthstone being unobtainable (and Emerald Blossom Dreamstone from Dragonflight Season 3) should still be obtainable past their respective seasons like Gleaming Incarnate Thunderstone from Season 1 of Dragonflight is? Or should they be unobtainable and patch 11.0.5 fixed the behavior of Obsidian Aspectral Earthstone still being rewarded.