Take the seed: 843417916 as an example,
The coordinates of spawn point in the old world are: x=1864,z=4;
In the new world, the coordinates of spawn point are: x=-16,z=16.
It can be seen that the two spawn points are far apart.
To observe this problem, we should first create and enter an old world in version 1.17.x and before, then determine the location of the spawn point (by returning to Overworld from the End), and at the same time ensure that the area where the spawn point in the new world is located is not loaded, then update the world to version 1.18.x and later, and return to the spawn point again in the same way, and it will be transmitted to the spawn point in the new world.
This time, I sent the seed and related pictures.
Please pay attention to the distribution of dandelion in the last 8 pictures. There are fuzzy boundaries in the distribution of these flowers.