I really struggled with this trophy and I was convinced it was permanantly glitched, however, having now achieved it, I thought I'd write down how I did it. I must admit, I did a lot of Googling and the technique I'll explain wasn't discovered by me, but actually gleaned from a few posts I read online. Whilst I cannot take credit, the fact that it worked definitely means it needs sharing.
This trophy was the last one I had to obtain. I'd managed to discover three possessed vending machines in a short space of time, and had killed two of them... on the third I died from the Hiss before I had chance to destroy it. I do wonder if it was this that glitched it, as afterwards, no matter how many times I traipsed around the DLC area, I could not find another possessed one.
I had read that you should quit the game and load the chapter 'End Game' - doing this actually wipes all progress from the DLC's and so is a difficult call to make. However, as this was my last trophy, and as I had backed up my save game to the cloud, I decided to give it a go. Given that you lose a lot of progress, and my level of frustration at the time, I turned on one hit kills and invincibility within the new Assist Mode found in the options. I then made my way into the AWE DLC section. The first vending machine I came up to was possessed, but then the next handful I found were not. After a while I decided to quit out and reload. Suffice to say, the next vending machine I hit was possessed - having shot it (with the assisted one shot) the trophy popped. I've seen different numbers from the various posts out there, but for me, I only needed to destroy 4 in total (although I've read it can take as many as 6 though).
Hope this helps.