Information

Full output of /ess version:

>.... [13:48:20 INFO]: Server version: 1.16.1-R0.1-SNAPSHOT git-Tuinity-"9f21359" (MC: 1.16.1)
>.... [13:48:20 INFO]: EssentialsX version: 2.17.2.146
>.... [13:48:20 INFO]: LuckPerms version: 5.1.26
>.... [13:48:20 INFO]: Vault version: 1.7.2-b107
>.... [13:48:20 INFO]: Citizens version: 2.0.27-SNAPSHOT (build 2019)
>.... [13:48:20 INFO]: EssentialsXChat version: 2.17.2.146
>.... [13:48:20 INFO]: EssentialsXSpawn version: 2.17.2.146
>.... [13:48:20 INFO]: ChestShop version: 3.11 (build 213)

Server log:

EssentialsX config:
latest (21).log

Details

Description
In 1.15, if you used Multiverse Core to block a player or group from accessing a world. EI having a creativeworld for just staff. You could set warps in there, but if someone who didn't have access tried to warp, he would be blocked from entering and it would tell them they can't warp there. Same with TPA. However since upgrading to 1.16 it now allows you to warp or teleport to the world using essentials commands, even though they are blocked with multiverse.access.

Steps to reproduce
warp or accept a teleport request from another player in the world.

Expected behavior
Expected players to be denied access when trying to warp to a blocked world (Multiverse Support)

This sounds like a problem with Multiverse, not Essentials. Please report it to them instead, or replicate the issue without Multiverse installed on both 1.15 and 1.16 to confirm that something else instead was broken in Essentials.