All skills can have their skill levels changed, including passive skills. (Screenshot)
(This caused some skill levels to get changed on skill bars)
Mounts:
Baby Ranger
(note: after using warg mastery I had to move to use mount again and I did not sit in the screenshot)
Multiple mounts have issues with their palette. Ones I have seen are paladin and knight with alternate color and I heard there was an issue with gunslinger's peco as well, I assume also with dye. I am sure there are probably more out there as well.
The Fox mount has positional issues. (Screenshot)
Other posts:
Disappearing Halter Lead
Edit:
Found screenshots for the Peco and Lion
Edited by NoxiousOrchid, 17 August 2011 - 12:28 PM.