I was playing on Refinery with a bunch of randoms at 3:48 pm. I was using the FAL and pushing the first point as Security. We had just captured the point and the counter attack was coming. I began to look around to look for incoming threats and suddenly I saw a IED drone in the middle of the point, just beneath the connector above us.
One of my team mates said they thought it teleported in rather than flying in, but I think it just didn't make any noise. It all happened in a matter of seconds so I honestly don't have a good handle on what happened, and unfortunately I don't use shadowplay so I don't have it recorded.
So, all in all, IED drones appear to be bugged. They are either spawning in on the location that is requested or flying in without making any noise.