An example:

Entity of type "Snowball" is at the position 0 0 0. A CommandBlock running the command "tp @e[type=Snowball,c=2] ~ ~10 ~" is at the position 10 0 0

What should happen:
The Snowball should move to the position 10 10 0 since the coordinates are affected by the position of the commandblock. Instead, the entity moves to 0 10 0.

So, the command "tp @e ~ ~10 ~" is the same as "execute @e ~ ~~ tp ~ ~10 ~". This already exists since version 14w07a.

I hope this is not on purpose.