2 or more Nether Portals are collapsing.

If the player enters in a portal, he/she will get to another portal
Example: Portal 1 (At X 100 Y 50 Z 100) and Portal 2 (At X 500 Z 60 Y 800) transport the player to the same portal in nether

there is a video: https://youtu.be/RUiO2oB8hyI