Some collected items from Dawn-Seeker vendors on Stormshield show as collected from a different item.

For example, I bought all four variants of the Shard-Convered Dreadcloak (Exceptional, Flawless, Ethereal, and the non-epic base item).

The Appearances UI shows I can transmog the appearance as any of those four variants.

However, the ALL THE THINGS UI (the list and the item tooltips) say that I only know the base and Exceptional variants. The Ethereal and Flawless items only have a black check mark on blue circle icon instead of the normal blue check mark icon.

I am having similar issues with the Crystalhide Belt, Crystalhide Legguards, Crystalhide Cowl, Crystalhide Bracers, Crystalhide Grips, Crystal-Edged Bladecloak.

Actually, I just tried turning on Completionist Mode and it fixed them after it says "Refreshing ALL THE THINGS collection status...". Why didn't clicking Shift on the Stormshield vendors do the same kind of refresh as Completionist Mode does?

Do these items have the 2hr timer on them still? If so, that is why. As long as the timer is there it won't register since you can refund them until then.

Nope. I bought them yesterday or the day before. I was selling them today after checking the 2hr timer was gone.

Try doing a Shift+Click on the "ALL THE THINGS" header when you do /att

Sometimes after you vendoring Blizzard doesn't send out the flag saying you learned it, but when you force refresh it should pick it up.

I tried Shift+Click on the Stormshield vendors. Are you saying that Shift-click and the Completionist Mode scans do the same thing? I don't think so, because Shift-Click didn't work and Completionist Mode did work.