I am attempting to use nether portals to speed up travelling longer distances; I set up portal near my base, at coordinates 302 / 64 / 168. In the Nether, I set up a portal above the upper bedrock at 38 / 129 / 21. When I travel to the nether from my overworld portal, I spawn in at a new portal at 38 / 88 / 21, but when I travel back to the overworld from the nether portal at 38 / 129 / 21 I arrive at the right portal. In summary, When I travel to the Nether from the overworld, I spawn at the wrong portal, but when I travel back to the overworld, I spawn at the correct portal. If anyone could help solve this problem it would be much appreciated, thanks.
Edit: I realize that this is likely posted under the wrong section
Because the Nether is limited to 128 high, the search algorithm will
neither find nor create portals at or above Y=128 in the Nether.
Therefore, for a portal in the Nether to be found, its lowest portal block
must be at or below 127. Any portal blocks above that are ignored by
the algorithm. Portals may be found or created above Y=128 in the
Overworld if there are no closer portals or valid locations.