When an entity is in another dimension, teleporting it to yourself while you are also in another dimension different from the entity. The entity will dissappear.

Example: A chicken is in the nether and you the player is in the overworld. Using the teleport command to teleport the chicken to you will cause it to dissappear.

Video Example 1 : Summoned 2 chickens, Chicken far away from the portal will dissapear when teleported.

https://streamable.com/xxk512

Video Example 2 : Summoned only 1 chicken.
https://streamable.com/hv7q20

Video Example 3: Summoned only 1 chicken with ticking area.
https://streamable.com/1hpg22

Even though the chicken doesn't teleport the command still registers the entity being teleported to you the player.

This also happens with custom entity with persistent and tick_world with never despawn as true. They would still dissappear upon teleport.
Also, happens when using the teleport method from gametest.