I finally took the opportunity to align my trunk. This has been a known issue since the 2010 Taurus/SHO and I've seen the same issue on 2015 models. My trunk on the driver side keeps rubbing against the fender and bumper cover, and there's nothing in the Chilton's online FSM or any forums discussing a resolution other than to have Ford look at it, report it, etc...
Procedure:
Anyhow, all you need is a 3/8" drive ratchet with a 8mm socket and a sharpie marker. Pop open the trunk, lift up on the black plastic ledge that covers the striker. It's held in by a bunch of those metal clips that grip slots in the sheet metal. Just lift up and it should come right out.
Use a sharpie marker (fine tip preferably) and mark the existing location of the striker. Because my driver side was rubbing, I moved the striker towards the passenger side. I loosened the bolts enough to slide the striker, snugged it to check clearance, and repeated until I liked the clearance. Torque the bolts to 12 N-m.
The FSM covers the removal of the trunk, the trunk latch, etc... but not the black plastic ledge or the striker for some reason.
Now when the trunk closes, it drops straight then instead of angles/slides towards the side that rubbed. It wasn't a hinge issue or fender issue. That said, my passenger side clearance between the tail light/bumper cover and trunk is a tad tighter than on the driver side - but everything else clears fine. I suppose this may be a structural misalignment or something. My hood is totally out of whack and it looks like the fender sheet metal wasn't installed correctly as one side of the hinge sticks up more than the other. I don't mind that or the huge gap towards the front because the paint isn't rubbed down to the primer/bare metal like it was on the trunk.
I hope this helps.