Third off, Naruto DID NOT LEARN the FTG technique. I strongly urge people to stop spreading lies. If it was FTG, then when he teleports, he would have appeared on the wall. There was no motion, so no reason for his leg smashing into the wall. What happened there was pure speed. When Bee said yellow flash, it was not referring to the FTG, but instead to the insane speed that Naruto's hair was a blur of yellow.
This is proof because it's simply common sense as well as physics. Kishi is smart, so I'm sure he intended this. If you still don't understand, then picture it like this.
I'm standing in between two walls, wall A and wall B.
Teleporting (FTG): I'm standing next to wall A, I teleport next to wall B, still standing.
Pure Speed (uncontrolled): I'm standing next to wall A, I move to wall B with blinding speed, but since this speed is so new, I don't have full control of it and I run into wall B, hurting my face badly.