From Destiny 2 Wiki
An engram with a predestined outcome. It will contain a new Exotic if any remain to be collected.
Fated Engrams used to be decrypted into an Exotic item that the player has not yet collected, with two limitations:
- Gear received from quests or challenges could not be obtained through these Engrams;
- Exotic armor used to drop only for the class of the character that got this Engram.
- The Fated Engram was also called "Isochronal Engram" in Xûr's inventory.
- Sometimes these Engrams bugged out and decrypted into items the players already owned.