Noticed for a while my guild tabard was always the wrong version when logging in, but digging into more I found that every aspect of guild customized items are broken.
There seems to be an EXTREME amount of spaghetti code going on here. All guild shirts appear as their sleeveless initiate version upon mogging. However, UI/character/tmog window shows the correct version. This visual bug applies to both the player(you) and other players viewing your character.
Oddly enough, logging in and out further changes every guild shirt to the artisan officer’s version. This also applies to both the player(you) and other players. Further login and outs for other players change the guild shirts back to the initiate’s.
So it seems:
Mog any guild shirt → appears as initiate’s ->login/out → appears as artisan officer’s-> Further login/out for other players-> appears as initiate’s
Also to note the guild tabards all appear as the base guild tabard upon login, however, this seems to only apply to the player(you). Other players still see it as the correct version if they were already zoned in. HOWEVER, if other players login in and out the player(you)'s tabard changes back to base version. Unlike the shirts though a simple unequip and equip fixes all visual bugs.
Guild banners also are gone entirely for other players. You are the only one who can see the guild banner you placed. This applies to ALL guild banners, and no login in or out changes it.
A lot of these bugs have been going on for a good while now as I’ve found reports of this as far back as 2023.