I like the idea to shred some raiders and shamblers with some 40mm shrapnel ammunition to tears, but I can't place the manned emplacements. Only thing working are the turrets, but my guess is because they are unmanned.

I see those manned emplacements in my security/combat category and can choose them, but when I hover over the position I want to place them, no blue "shadow" is seen as like with everything else. When I click, the game do not give any feedback that something is missing, like ground support or something in the way.
When I move the cursor in a way that the operator spot would be not available (like a wall or a tree at the spot) the "shadow" is visible in red and the game gives me feedback something blocks the operator spot. Is it an issue on my side or is somthing broken?