The first Tier 8 delve (bountiful) i did today with my main only shows as Tier 1 reward in the Vault.
The 2nd Tier 8 counted as 8 and the third too it seems.
Now i am at Vault slot two and it still shows as Tier 1 (from the first bugged run i guess).
So is this just a visual bug or do i need to do 9 Tier 8 now instead of 8 to be sure?
EDIT: after the fourth it seemed to have fixed itself, now gives Tier 8 on both slots
I had the same issue.
Levelled to tier 7 on alt to avoid getting lower level map drops on main.
Main does tier 8 as his first delve this week, shows up as tier 1.
See attached screenshot.
Have done 5 tier 8 dungeons how, Great Vault World track correctly shows up as 2 x 616 and a lower piece based on world activities.
So maybe the error on the single delve completed is because it “caches” the world activity ilevel.
Mine shows 1 tier below what I actually did.