Turret spawning on roof light

[Bellbo]

Hi there, just found an unusual turret spawning bug, whereby the turret spawns on the same square as a "roof light" on an advent building (in fact 3 turrets on 3 roof lights in this case - the roof light to the right of the screenshot is out of vision so the turret doesn't show up).

I'm using LW 1.1, win10, no other mods, legend recover item mission (mid July), have a save if needed.