Dwarf foretress
Yep happens sometimes, escpecialy on wall edges. Denostructing and constructing again fixes it.Unfortunately, if there are stairs or ramps nearby, deconstructing and reconstructing doesn't always fix the problem. I was hit with the bug twice, and in both situations the only workarounds were very tedious (removing the nearby stairs/ramps, or designating the wall as a low-traffic zone).
Is using search that hard (http://forum.meleegaming.com/and-all-the-other-things-floating-around-out-there/dwarf-fortress-11718/)?
All them dorfs had quivers and bolts, but well, new fortress on the go. Losing is really fun aslong as you can see civilian dorfs go on a killing rampage :)