Bugged Characters

Hi,

I'm totally confused.

I noticed that almost all of my characters are not displaying uninterruptible casts correctly.
My main and one level 1 character are the only chars that show the special border for not interruptible spells or items like the hearthstone.

I thought it was an issue with addons, so I tested it in 1) a no addon client and 2) a 3.3.5 client from a different server. Both had weird results.

The uninterruptible border for my own and other players casts is not shown on some chars at all. I managed to create a few chars on Blackrock that DID show the border but I couldn't figure out what made the difference.
For example: Human Female Paladin did not show border. Dwarf Male Hunter did(but only after i got the marksman spec&equip from the NPC). Gnome Male Deathknight showed it from the start on.

If anyone has a clue what could cause this I would really appreciate help.

Edit: I should probably mention I tested this on 2 accounts and both have the same bug.