I completed a +15. Timed it with a few seconds left.
Almost immediately after we looted the chest was when the world server crashed (yesterday 6/7)
It still hasn’t showed up in my dungeon guide/instance journal in WoW.
It’s updated on RaiderIO. Right after it was completed as a matter of fact:
https://raider.io/characters/us/sargeras/%C3%96rpheus
It was also my 4th mythic for the week which caused me not to be able to get a 2nd dungeon vault slot. (I’ve stopped caring about this part at this point) This will never get fixed.
What the hell am I supposed to do? Just wait? My ticket was “answered” with a generic ‘go to’ response. Wait.
I’ve waited.
I don’t really have the time to play all the time. I am trying to get KSM and being robbed of a dungeon run sucks.
Ticket response:
"Thank you, Orph, for contacting us, this is Game Master Lavasurk and I am here in regards of your ticket about the Great Vault but firstly, I’d like to apologise for the waiting time. Thank you for your understanding.
The Great Vault may not immediately update as content is completed. Our developers are working to make these updates happen faster.
In the meantime, if your Great Vault does not update, you can try relogging to see if that refreshes your Great Vault. If that doesn’t work, you’ll simply need to wait until the update occurs naturally.
Keep in mind that the Great Vault may display seemingly outdated options that do not correspond with your actions last week - this occurs when you don’t open the Great Vault during a full week. The options will remain the same until you choose a reward, at which point re-opening will offer you the next set of options for the week after.
In case you were wondering how can you leave feedback if you don’t like something here or you have any ideas - I invite you to join our forums: https://us.forums.blizzard.com/en/wow/ or share it through in-game feature: Esc → Help → Suggestions. I also confirm that I will add this to our internal data base, this is how our developers are collecting information from our players regarding such issues.
If you have any questions that we may answer or if you need any help, please let us know, we’re more than happy to assist 
Best Regards
Game Master Lavasurk
Blizzard Customer Support"