Look rotation viewing vector is zero
Spamming non-stop, and the only recent plugins i have added was town teleport, command rate limiter, rock block, and command block, also entity limit. i tried unloading them and still kept going, any ideas ?

(13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero (13:05:17) | Look rotation viewing vector is zero
The message itself is likely a debug message caused by Rust itself.  That said, I wouldn't exclude the possibility that a plugin may be responsible for having created an entity with an invalid look rotation.

It's unlikely to be Command Rate Limiter, Command Block, or Entity Limit.

I'm not entirely sure what Rock Block or Town Teleport do, if they have anything to do with the look rotations of players (it is atleast possible).
town teleport, just teleports you to the bandit town, or outpost, and the rock block just blocks players from building inside rocks, but i did removed it from the plugins and it just kept spamming it, i actually unloaded all the new plugins i have added, and it just kept spamming it.

https://umod.org/plugins/rock-block
As I said the message is likely from Rust, not a plugin.  Even if a plugin is the cause, the entity with the invalid look rotation must be a) given a valid look rotation or b) deleted.
Well i looked over rock block and i see in the code.
private bool IsInCave(BaseEntity entity, BasePlayer player) { var targets = Physics.RaycastAll(new Ray(entity.transform.position, Vector3.up), 250, worldLayer); foreach (var hit in targets) { //var collider = hit.collider.GetComponent(); //if (collider != null) SendReply(player, $"Cave: {collider.sharedMesh.name}"); //if (collider == null || !collider.sharedMesh.name.StartsWith("rock_")) continue; if (!hit.collider.name.StartsWith("rock_")) continue; return true; } return false; }
That's probably not the problem: it doesn't create an entity or update an existing entities look rotation.  That code just checks if the ceiling mesh has the string "rock" in it's name.
Well like you said perhaps it's with rust because those are the only plugins i added and it just started happening when the new rust update came out. So i guess ill just wait and see if they release another update but thanks for the fast replies though. Appreciate it. 
Upon further research, this is actually a Unity message when the Quaternion.LookRotation method is used improperly.  I doubt any of those plugins use that method directly.  There still may be an indirect relationship, but it's unlikely isolated to those plugins.  In any case, I would not be surprised if it had something to do with the new cargo ship and fixing it is probably under FP's purview.
In response to Calytic ():
Upon further research, this is actually a Unity message when the Quaternion.LookRotation method is u...
Yeah that's what i was started to think, it has to do with the cargo ship. Thanks caly. :)