(MOST)Agents won't reach the final destination

Hey, so i'm doing a 3D shooter with TD elements, the agent spawn in a circle around the center of the map(that's 0,0,0 in world space).

this worked for the last month or so(since i implemented it), now all i've done is rebake the navmesh because i changed the terrain a bit and it's barley working, using Unity 2017.4.3

as you can see, all but 2 in this case are stopping way before they reach the destination needed, I have no idea why this is happening.

as far as i can tell the red line indicated the path the agent will follow, i don't know what the orange circle and lines mean, I looked over (I think) all the navmesh and navmeshagent docs i could find, didn't answer any of these questions.

this is the code that controls the agent:

Code (CSharp):

1. protected override ManualUpdate(){
2.         if (agent.hasPath == false && agent.pathPending == false) {
3.             if (agent.SetDestination (Vector3.zero) == false) {
4.                 Debug.LogError (string.Format ("Agent at:{0}, can't get a path!", transform.position)); //This have never showed up
5.             }
6.         }
7. }
8.  
9. public override void Ini (){
10.  
11.         agent = GetComponent<NavMeshAgent> ();
12.         agent.stoppingDistance = minRange;
13.         sqrSpeed = agent.speed * agent.speed;
14.     }
15.  
16. public override void SpawnObj (Vector3 pos){
17.  
18.         if (agent.Warp (pos) == false)
19.             Debug.LogWarning (string.Format ("Enemy {0} couldn't reach target position! {1}", transform.name, pos));
20.         agent.ResetPath ();
21.     }

 

Does any one have any idea?
or at least knows what the orange circles and lines represent in the navigation window?

 

So I just did some more testing and if the agent is like at the picture name "Nav1" and i manually move him closer than(or then?) the orange circle it immediately turn to a red line and it walks fine to the center.

The F***?

 

So I sort of fixed it, i figured out that the orange line indicates where the path goes stale, I have no idea why because the docs say "This flag will be set if: there are any changes to the areaMask, if any OffMeshLink is enabled or disabled, or if the costs for the NavMeshAreas have been change" I don't do any of that, but it still goes off.

they way i worked it out for now is like this

Code (CSharp):

1.         if ((agent.hasPath == false || agent.isPathStale) && agent.pathPending == false) {
2.             if (agent.SetDestination (Vector3.zero) == false) {
3.                 Debug.LogError (string.Format ("Agent at:{0}, can't get a path!", transform.position));
4.             }
5.         }

BUT I'm extremely unhappy with this code, it runs way too much, and the agents that can't get a full(not stale) path from the get go will calculate a path for every navmesh polygon between the orange circle and the real destination.

please, help, someone from the unity team, i'm lost, what's happening here?