When using the /tp command on a player that is currently shifting the orientation of that player will be reset to 0.

Tested with a commandblock clock:
1. Create a commandblock with

/tp @p[r=5] ~-1 ~ ~

(or something similar)
2. Connect it with a simple clock
3. Walk in the detection radius: You will be teleported correctly, without changing the orientation
4. Now sneak and walk again into the radius: You will be teleported, but now looking in another direction (always 0, see debug screen).