A few of thoughts:
What happens if you delete the two rebels and perform a new copy?
It may be possible that the "copy path" is not 100% parallel with the wall. Try pulling the two rebel lights slightly off the wall and see if there is any improvement.
Last relaunch Enscape
I would guess those lights have been placed in SketchUp with an array and have not been place exactly parallel with the wall and are progressively nearer/inside the wall
If you look at the 3rd one (1st with a tick) you can see that it doesn't quite reach the parapet, I agree with what's been said above, they seem to progressively get closer to the wall going right to left ... or the wall isn't perfectly parallel to the axis.