Performance issues and lag
The NRE is likely unrelated to the warning, check your logs for the full error. The warning has an existing thread for it.
Seeing a lot more of this since today's update, like this over and over in the logs;

Calling 'CanBeTargeted' on 'Vanish v0.7.7' took average 1389ms
Calling 'OnNpcPlayerTarget' on 'Vanish v0.7.7' took average 1390ms
Calling 'OnNpcPlayerTarget' on 'Vanish v0.7.7' took average 1441ms
Calling 'OnNpcPlayerTarget' on 'Vanish v0.7.7' took average 1449ms
Calling 'CanBeTargeted' on 'Vanish v0.7.7' took average 1423ms​
Just had this pop up in my console.

GugZEmT.png
Disable this plugin for now. it cause super lag for my server. couldn't move 
as soon as you disable it you will see a massive improvement.
You could jsut comment out that hook
OnNpcPlayerTarget​

thats what i did and no errors since then or lag

5d3c7df619f1d.png RocketMyrr
You could jsut comment out that hook
OnNpcPlayerTarget​

thats what i did and no errors since then or lag

In the .cs file?

Yup. Just search for that hook and comment out thoose lines for that hook. As he has already onnpc target right below
The OnNpcTarget hook usage in this plugin currently only handles BaseNpc... which is animals only.

The OnNpcPlayerTarget hook usage is only handling NPCPlayerApex, which is the older Murderer NPC.

The correct solution to fix this would be to remove the OnNpcPlayerTarget hook entirely, and change the BaseNpc part of OnNpcTarget to BaseEntity or BaseNetworkable to cover ALL NPC types in Rust (BaseNpc, NPCPlayerApex, HTNPlayer, ScientistNpc, NPCPlayer, etc.)
Nice thank you!!!. Was always able to be seen by the scientist and npcs. Now am fully invisible to them. 
How do I fix this?
I mean why not just update that plugin instead

Merged post

@RocketMyrr what line of code have you changed in the 0.7.7 version of Vanish ?

Merged post

What do I need to change in this ?

// Hide from scientist NPCs
        private object OnNpcPlayerTarget(NPCPlayerApex npc, BaseEntity entity)
        {
            BasePlayer basePlayer = entity as BasePlayer;
            if (IsInvisible(basePlayer))
            {
                return true; // Cancel, not a bool hook
            }

            return null;
        }

        /*private object OnNpcPlayerTarget(HTNPlayer htnPlayer, BasePlayer basePlayer)
        {
            if (IsInvisible(basePlayer))
            {
                return true; // Cancel, not a bool hook
            }

            return null;
		 
        }*/

        // Hide from all other NPCs
        private object OnNpcTarget(BaseNpc npc, BaseEntity entity)
        {
            BasePlayer basePlayer = entity as BasePlayer;
            if (IsInvisible(basePlayer))
            {
                return true; // Cancel, not a bool hook
            }

            return null;
        }
Remove:
Subscribe(nameof(OnNpcPlayerTarget));


Remove:
Unsubscribe(nameof(OnNpcPlayerTarget));


Remove:
// Hide from scientist NPCs
private object OnNpcPlayerTarget(NPCPlayerApex npc, BaseEntity entity)
{
    BasePlayer basePlayer = entity as BasePlayer;
    if (IsInvisible(basePlayer))
    {
        return true; // Cancel, not a bool hook
    }

    return null;
}


Change:
private object OnNpcTarget(BaseNpc npc, BaseEntity entity)

To:
private object OnNpcTarget(BaseEntity npc, BaseEntity entity)


Works for animals again, and seems to be half-working for other NPCs now. I'm guessing more tweaks will be necessary to get it fully working.
Change
private object OnNpcTarget(BaseNpc npc, BaseEntity entity)​
to
private object OnNpcTarget(BaseNetworkable npc, BaseEntity entity)​
That will make you completely invisible to all NPCs
@RocketMyrr Thanks for the corrections, with this i am invis to Oilrig,Excavator but Cargoship npc's can still see me. Any ideas on how we can fox this as well?

update: seems roadside npc's are able to see me as well
update2: Disregard all so far this is happening on a friends server with not newest umod he will update tonight so i can verify. On my server with newest umod it works! :)
It has been 2 days and still no update! 

Servers are suffering, please get it updated.