If a player is vanished and you leave the game and go to the multiplayer menu, the player will still show up in the list but when you join the game there will be one less person if you type /list
This has been getting on my nerves because now I can't follow people in vanish without everyone on the server spamming in chat that there is an admin invisible.
Please fix this

I can't reproduce that. Maybe one of your other plugins is playing with it. Can I get some screenshots and explanations of when this happens?

Here, in this screenshot I join the game silently, but when I join the game and don't unvanish when I refresh the multiplayer list it says that there is one person on even when I am in vanish.

So basically, when my members see the playerlist they remember how many people it says on and then when they join they type /list and that tells them how many people are on, but the /list is effected with the essentials hook, so it will be 1 less than the playerlist on the bottom. Please try to fix this.

Oh! I totally misinterpreted what you were saying. That is currently not possible with just VNP running on its own, but if you install ProtocolLib it will start hiding that player.