I have the wayfarer's tent, but no achievement. I have donned the entire set of glacial frost ornaments and copperleaf, no credit.
Hold the bonus items in your inventory until the whole achievement is completed. Hero's Forge is slightly the same way, it will only be checked off while it is slotted until the whole achievement is completed. If you take out the ornament before the ach is completed it unchecks. This is the way the scripts work.
The copperleaf achievement did not make it into game until January. https://forums.daybreakgames.com/eq/index.php?threads/game-update-notes-january-17-2024.295544/ Also even if you can equip it, you can only get the achievement for your class armor type. Cloth can slot leather but cannot get the leather achievement, only cloth. This is for the standard ones, it seems you can get the 2 for your archetype for the crate ornaments.
Theres still the ach cache issue that can happen, uncheck all 3 filters at the top then recheck. And every single item works the same way, you only get it checked if its in inventory until the whole achievement completes. If you put it in house or bank it will uncheck. You need all 5 16th items at the same time to complete it. - 'Metamorph Totem: Speckled Hare' from 'Belle of the Ball' - 'Necromantic Dragon Bone' from 'Dead Dragons' - 'Sarnak Seneschal Mask' from 'Korukust's Royal Pain' - 'Golden Helm of Rallos Zek' from 'Liquid Courage' - 'Shimmering Black Pearl' from 'Pirates of Timorous Deep'