Using Local Coordinates to teleport results in incorrect destination

when teleporting using ^ ^ ^, if player facing angle is not 0,0, the player will be teleported lower than expected when teleporting great distances.

 

 

To recreate, create new world in 1.21.4, do NOT move mouse, enter creative, go into fly mode and hover around cloud height. watch Y pos, and use /tp @s ^ ^1 ^100. this should teleport you 100 blocks forward in whatever direction you're facing, +1 block up. then change your viewing angle, and repeat the command. this will result in the player being lower than they had started, and over greater distances, the player can end up under the world. the amount displaced downwards seems to vary based on the angle before issuing the command.