Like the title suggests, the 3D objects you can view in most of the inventory menus are off-center (too far to the right) in the smithing menus. It could be this way in other menus as well (i.e. alchemy, enchanting), but I haven't played that far to see.

The only mod I have that could possibly be the cause is SkyUI. Is this a common problem with SkyUI, or might it just be a bug with my game/save?

SkyUI's menu item setting will affect its placing, resulting the off-center placement in menus that are untouched by SkyUI.

You either have to ditch SkyUI, or learn to live with it until someone can make a SkyUI version of crafting, enchanting, and alchemy menus.