World doesn't save where you left off

I traveled 150,000 blocks away from spawn using firework boosting, then I saved and exit from the game. When I logged back into the same world I spawned 70,000 blocks away from where I was! When I left the game my X coordinates were 150,384, then I logged back in and was at 89,625, this glitch will become frustrating in a survival world

• steps to reproduce*
  1.load up a new world in creative
  2 Teleport yourself to at least 150,000 blocks from spawn
  3.save and exit
  4.log back into the world and it should spawn you farther back than you were at