24w21b has made significant changes to portal linking logic that serves to break a lot of technical contraptions that rely on precise control of the chunkloading ticket invoked by entities passing through a nether portal.

The following code introduced in 24w21b shows logic which sends the chunkloading ticket to the position an entity arrives in the other dimension. A world download is included with a test setup to verify the behaviour and its changes:

This runs contrary to the previously established behaviour where the chunk loading ticket is sent to the position of the portal block which links to the portal in the dimension where the entity enters the portal. Meaning a change to this behaviour would break a lot of technical contraptions that rely on precise chunk loading using nether portals.