Teleporting between dimensions using commands duplication bug

[Joseph_peace]

Title pretty much gives you the summary.

The long versions is that if I install Forge (tested with 1.14.4-forge-28.2.0, 1.15.2-forge-31.1.0, and 1.15.2-forge-31.1.47; with and without any mods), and try to teleport an entity, for example a cow, to the nether using the following command:

/execute as @e[type=minecraft:cow,distance=..10] in minecraft:the_nether run tp 0 130 0

then you get the confirmation message that the cow was teleported, but the cow does not disappear.

Also, if you travel to the nether coordinates, you will find that a cow did spawned there, but the original cow did not disappear, in other words duplication occurred.

This does not happen in vanilla Minecraft; it works properly in vanilla Minecraft.

Also, there is no duplication in Forge versions if the cow physically walks through a nether portal instead of using commands.

 

For further testing, I tried naming the cow then teleport it using commands, and surprisingly the new nether cow had the same name.

Also for further testing, if I try to teleport the cow more than once, only one cow is spawned in the nether; but if I kill the cow in the nether, and teleport the overworld cow again, another cow spawns in the nether. In short, only one duplicate cow can be spawned in the nether at one time.

 

I don't know if it will help much, but I am including the debug.log for each of those versions because the EAQ said so:

1.14.4-forge-28.2.0: https://paste.gg/p/anonymous/9720fbedd6464974abe7d93c6e810585

1.15.2-forge-31.1.0: https://paste.gg/p/anonymous/6af7331b35a24b69be02997cfa0fb77b

1.15.2-forge-31.1.47: https://paste.gg/p/anonymous/7a60654f91ef4d1e88d10862eaff0753

Edited April 23, 2020 by Joseph_peace
typos and wrong links