command block argument bug

When the command /tp @a[y=82,r=1] 109 84 -59 is entered into a command block, nothing happens. when it is entered into the chat normally by a player it works. When I try taking out the radius argument it teleports people from anywhere /tp @a[y=82] 109 84 -59. The reason I want this command is to teleport players automatically to a checkpoint when they fall off of parkour down to a certain level. theoretically the command being run by a clock should teleport people to the checkpoint when they fall onto the plane of y=82.

Steps to Reproduce:
1. make a platform to fall onto
2. make another platform to be teleported to
3. put a command block with a clock hooked up to it to teleport people somewhere nearby
4. type in this command with the blanks filled in [tp @a[y=(platform level),r=1] (coordinates of other platform)]
5. stand on the platform.
6. watch as nothing happens.
7. put command into chat and watch as it does work