Not really a game-breaking bug, but still:
On the shoulder parts of the costume there are outlines that should be silvery like the rest of them (e.g. the ones on the boots), but they're the same color as the shoulders instead (both in the costume's base colors and a dyed version, they take a slightly darker hue than the color you use in the first "dye slot"). They only get silvery when you sprint while riding, and stay so just for a few seconds after dismounting - wouldn't really have noticed them if it wasn't for that weird detail.
Apparently, Gothren's robes have that same bug, when he was walking towards my character at the end of a quest the outlines on were fine, as soon as he stopped they turned the same color as the rest of the shoulders. Same goes for Therana and Dratha's robes, of course. :P