Why is it that I hit the second vault slot at 616 my 3rd slot says do a 6 or over and I do 3 -8level delves and still no advancement from 584??? but if I do a 4 it advances a little I try to advance 3 characters every week and this is crazy train. makes no sense.
It’s likely because the Delve Vault category is combined with the WQ vault category and the lower end of your completion (WQs and anything under an 8) is skewing the reward lower. I believe you have to do at minimum 8 Tier 8 delves or higher to get the last slot to 616.
I have done 3 -8 delves and still wont advance
You need to do 4 iirc for 2 616 slots and 8 for all 3 slots to be 616.
The vault gives you a reward slot for the 2nd, 4th, and 8th hardest thing you did in that category.
You ave done 3 T8 delves and the rest world content, so your 1st slot is awarding 616, and the other 2 are awarding 584.
1 more T8 get you the 2nd slot 616
5 more gets you the 3rd slot 616