This is NOT a bug !
If it was, no one would be able to complete Season 28 OR the Altar of Rites.
I was able to do this on all 3 Regions. And that was over 2 weeks ago.
Hint:
- Rare Level 70 items start with the prefix Sovereign.
- Rare Level 70 Scythes start with the prefix Grandmaster.
- Rare Level 70 Phylacteries start with the prefix Embalming.