When a command is executed that tests for coordinate position, the x, y, z, and r values are only accepted if they have x=, y=, z=, and r= in front. This happens even if these four values are the first four arguments. According to the Minecraft Wiki, "If the first few arguments (up to four) are specified simply as values without identifying the arguments, they are assumed to be, in order, x, y, z, and r." I am not aware of any changes to this in recent snapshots, so I believe this to be a bug.

The first photo shows a kill command that targets the creeper and uses coordinates WITHOUT the x=, y=, z=, and r= in front. Notice how the coordinates used are very far away from my current location, so the creeper should not be killed.

The second photo shows the creeper dying when it should not be. The coordinates were effectively ignored from the previous photo.

The third photo is like the first, except it uses the x=, y=, z=, and r= in front of the coordinates.

The fourth photo shows an unharmed creeper and the command works like it should normally.