I've restarted the game and run verify/repair twice and the Dol Blathanna armor isn't in the chest with the White Tiger armor and the Nine-Tailed Vixen steel and silver swords. Geralt's witcher senses still highlight the chest but there is nothing in it. Both the armor and swords are there are level 11, so not immediately useful to a level 4 Geralt. I'm just confused because other things I've read suggested that there should be a second armor set in the chest (in Yennefer's room at the palace in Vizima). Am I just misinformed or this is a bug? It seems odd that it would still highlight if I'd taken every that was supposed to be in it. The armor was missing both before and after my restart and subsequent verify/repairs.

I can confirm this.

But honestly, it is just one bug/glitch out of many that were introduced with the Remastered version.

It's not a bug.
You need to register/link accounts, see https://www.thewitcher.com/us/en/my-rewards#instructions
If you don't, you can only find 1 armor set and Yen's letter in Vizima.

You can add the items using the console.
Geralt's gwent card however will not get the muster ability.

To enable the console, open the installation directory and go to \bin\config\base and open general.ini. Add the following line: DBGConsoleOn=true

Console commands:
additem('Dol Blathanna Armor')
additem('Dol Blathanna Pants')
additem('Dol Blathanna Boots')
additem('Dol Blathanna Gloves')
additem('Dol Blathanna longsword')
additem('White Widow of Dol Blathanna')
additem('gwint_card_roach')

This step is necesseary for the Scarlet Crest Armor set. But we are talking about the missing Dol Blathanna Armor that came with the Next Gen edition.

Could be I'm wrong on the account linking. You might only have to play it through Galaxy.