Seasonal autosave of a fortress that should get a siege at some point in that season. There are several bolt throwers on the surface that do not fire on invaders, or fire inconsistently.

I was able to get them to fire once by having the siege engines set to "fire at enemies" before the siege arrived, but the next time I tried the same thing it didn't work. This doesn't seem to be a line of sight issue, since the bolt throwers are on the same level as the invaders, and there's just one fortification between the siege engines and invaders. The invaders will pass quite close to the fortifications, often even walking adjacent to them, with no reaction from the siege operators.

Previously in this save I was trying to dump some bolts out of the bolt throwers, but that clearly didn't work since they're all still in the bolt throwers. I was wondering if this was the problem as well, but un-dumping/un-forbidding the bolts before the siege arrived didn't solve anything, and deconstructing the bolt throwers and rebuilding them didn't have an effect either.

Most of the bolt throwers on the map are new since the previous invasion, but the previous emplacements did seem to work properly. The bunker on the East side of the map and the tower at the South both existed previously, and have fired on sieges and surface beasts just fine up until now. The bunker at the North and the two emplacements on the sides of the large central building are new for this siege, but they should be functionally the same as the East side bunker.

This save uses Detailed Landscapes 2.1 and Intro's Kobold Civ 1.41. Note that I am using an older version of the kobold mod (its currently up to 1.47), but I don't imagine that is having an impact here. There has also been an appreciable amount of DFHack usage in this world.