Using a repeat command block with a command like /tp (player) ^ ^ ^3 will not teleport in the direction the player is facing. Instead, it makes the player get stuck in one spot, and it made me have to delete my minecraft 1.13-pre7 world.

How to reproduce:

Run /give (player) command_block. Place it down, type "tp (username) ^ ^ ^3 and set it to repeat. Put a lever on it and flick the lever. It does not work the way it should.