Can't place AP mines on... extension cord?

New Sobek City, one (or more) of the construction site buildings has an extension cord just laying on the floor. I'm inside, I look out the window and see someone coming, and I try to put an AP mine on the floor near the door... but it won't place, and while I'm trying to find a spot quickly, he comes in and shoots me. I later come back and blow up some debris I thought was the problem, but it was just that extension cord laying on the ground.