Playing as Warlock (you know RestedXP has a way to copy a lot of information that might be useful for pasting into bugs here).

Message in console

[Worn Leather Pants] has been added to your appearance collection.

It does seem to have sold them, so maybe this is just a tooltip issue.

Presuming the property in the item being looked at is HasAppearance that is set to true.

Game Version 11.0.0
Vendor 6.6.0
Not certain how to get the client version with the game open, feel free to let me know. Up to date though as on July 28th 2024