Your Covenant's Flavor

6/16/21 -
I am a Necrolord Shaman, and the Rank 5 Abomination Factory was the last upgrade I crafted for my covenant.
After finishing the Rank 5 Abom Factory, I did not receive credit for this achievement. Thinking that perhaps I needed to do the quest line for "Unity" (final abomination) to earn the credit, I did that as well. Still no credit.
Because this achievement is needed for credit towards "Restoration Expert" - I am missing that as well, even though my covenant is completely upgraded.

I opened a ticket with customer support. They just got back to me with this:

Thanks for contacting us to let us know about this bug! It's great when players such as yourself take time to contact us, it helps improve the game for everyone.

I can confirm that we have had reports of this and our developers are currently investigating to see if they can locate any issues with the game mechanics.

Sadly we don't have a temporary workaround to apply at this time and I suggest you to open a bug report directly to the developers (the more reports the higher the priority)

To submit a bug report in World of Warcraft please open the game menu [Esc] and go to "Help". There you will find a blue bug icon; you can submit your bug report directly to the developers from here.

One thing to note is that you'll not actually receive a response if this bug is confirmed and addressed. So you'll need to keep an eye on the patch notes on the website after a patch!

GM Khrastalius - Customer Support - Blizzard Entertainment

Apparently, you need to upgrade the Command Table to Rank III first. This achievement popped up for me the moment I got [achievement=14636].