So, we've used the TP Command for our minigames for quite some time now and have come across (what we think) is a HUGE issue with a 1.8 prerelease.

Our issue involves 1.7.x - later.
We have a few command blocks setup with TP Commands. These commands are as follows:
tp @p -574 82 80 2
tp @p -578 82 80 2

Basically, the CMD Block output is saying that "You must specify which player you wish to perform this action on." after we hit the button.

This has worked flawlessly (prior to 1.8 pre-r 2) adding the extra parameters for a "Directional" TP Value.

Are there any extra syntax options we have missed? I've scanned the Minecraft Wiki thoroughly which didn't help.

This has left me thinking is it an actual bug? Or are we doing something that hasn't been properly explained?

Sorry if it dragged on, I can't explain things quickly.

Also, the carpet stays attatched on piston extension and dissappears on piston retraction.

Carpet in placed on a slime block.