There are two wall mounted weapon racks in the Mistveil Keep Jarl's Quarters. One has a steel greatsword, the other an elven greatsword. Both are unlootable due to the weapon being placed too far into the wall.
An identical issue for a weapon rack in the main keep was fixed in v2.0.8 (2014-12-06).
"000E620E, 000E620F: A weapon plaque and its activator were placed too close to a wall making it impossible to activate a steel greatsword [Ref 000E620D] in Mistveil Keep. (Bug #17931)"
Ideally, IMO, the weapon racks would also be usable by the player to put something back in their place. If that's accepted as a bug, it also applies to the other racks in the main keep, and floor mounted racks, and in the barracks, and probably many other locations.