LibGDX camera position shifted on movement

Question

I'm programming a game with LibGDX and Box2D and I want my camera to follow my player. But as I zoom in (because Box2Ds metric system, using camera.zoom = x) the camera is shifted when the player moves (the camera follows the player):

Shifted View

Normal View

That only happens when the player moves, so there can't be a problem with the coordinates. My Question is how to remove this shifting as the player moves.

Here's some of my code:

Render Loop (excerpt):

@Override
public void render(float delta) {
    //set the camera position to player's position
    cam.position.set(player_body.getWorldCenter().x, player_body.getWorldCenter().y, 0);
    cam.update();

    world.step(Gdx.graphics.getDeltaTime(), 6, 2);
    world.clearForces();

    handleInput();

    Gdx.gl.glClearColor(.05f, .05f, .05f, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    batch.setProjectionMatrix(cam.combined);

    debugRenderer.render(world, cam.combined);

}

Make the player move:

if (Gdx.input.isKeyPressed(Keys.W)) {
    player_body.setLinearVelocity(transX, transY);
    player.setMoving(true);
}

Answer 1

Okay, I found an answer. You need to set the camera's position directly after calling world.step() and then it works without shifting.

world.step(...);
camera.position.set(...);
camera.update();

(Original Answer)