I'm wondering if this is an actual bug, or if I'm just not clicking on some update that I should be. I did click on the "update achievements" button before posting, so I don't think that's the issue. I didn't want to post this on the Bugs forum yet because I'm not sure if it's a bug or just me being anti-observent. :)

You have to go to your User Dashboard to update the achievement and collect your Loyalty Boxes. Note that there's an issue with the boxes currently so you'll probably need to file a ticket to get the ones you're missing.
And you should also get a 1 Week GA + achievement for being here for a year or longer. That one's retroactive and not a glitch.