I have gone into my wardrobe and added items to my avatar several times and they are not showing on my avatar.
Here is what I am doing:
wardrobe ---> items ---> only items i own ---> click item I want to wear ---> wear now
says "wearing on site!"
Then I go back to subeta and my avatar is unchanged.
I'm having this issue too, which is awkward because I'm wearing everything except pants and a shirt, lol
The items that won't show up are ones that I purchased after making the outfit, which I tried to wear after purchasing but they won't stick.
Editing for more detail:
If I fully exit the wardrobe, return to the wardrobe, equip the items (both individually and from the outfit), and click 'wear on site', (with 'now wearing on site' notification) then fully exit the wardrobe again and return to the wardrobe the items will no longer be on my HA.
**editing for my workaround
I found a workaround for the issue I was having, not sure if it's the same for you! I tried equipping items I didn't have, and then trying to wear the outfit after I bought the items wouldn't add them to my HA.
If you equip a different outfit, add the problem items to your HA, and equip that, then try the original outfit and see if that makes them equip normally.