Great Vault: No Upgrades?

Coming back to this game and taking progression seriously for the first time since Cataclysm/Pandaria, so still learning a lot of the new systems…

thanks to LFR and the 20th Anniversary Event I’ve been able to get some pretty great upgrades (600+ iLvl) for my new Main… but I did 8+ Raids and Dungeons last week, managed to fill All the slots in the Great Vault for items to generate, and every single one is a downgrade / worse than what I already have??

Is that typical or is the Great Vault bugged??