Null Reference on Start "GatherDelegates"

[nvyvestudiosParticipant]

Hi there, we are attempting to upgrade our game from 2017.2 to 2018.3, and are now receiving this error on start for each NPC in the scene:

NullReferenceException: Object reference not set to an instance of an object
NodeCanvas.StateMachines.FSM.GatherDelegates () (at Assets/ParadoxNotion/NodeCanvas/Modules/StateMachines/FSM.cs:219)
NodeCanvas.StateMachines.FSM.OnGraphStarted () (at Assets/ParadoxNotion/NodeCanvas/Modules/StateMachines/FSM.cs:59)
NodeCanvas.Framework.Graph.StartGraph (UnityEngine.Component agent, IBlackboard blackboard, Boolean autoUpdate, System.Action
1 callback) (at Assets/ParadoxNotion/CanvasCore/Framework/Runtime/Graphs/Graph.cs:646)
NodeCanvas.Framework.GraphOwner.StartBehaviour (Boolean autoUpdate, System.Action1 callback) (at Assets/ParadoxNotion/CanvasCore/Framework/Runtime/Graphs/GraphOwner.cs:110)
NodeCanvas.Framework.GraphOwner.StartBehaviour () (at Assets/ParadoxNotion/CanvasCore/Framework/Runtime/Graphs/GraphOwner.cs:103)
NodeCanvas.Framework.GraphOwner.Start () (at Assets/ParadoxNotion/CanvasCore/Framework/Runtime/Graphs/GraphOwner.cs:209)

Updating to the latest version of NodeCanvas on the asset store unfortunately did not fix the issue. We dug around a bit and couldn’t find a clear cause as to why this would now be happening – any assistance would be greatly appreciated!

[GavalakisKeymaster]

Hello and sorry for the late reply due to xmas vacation.

Hmm. Is there by any chance, a “missing script” attached on the FSMOwner gameobject?
You can also do a null check at the start of ‘GatherDelegates’ method (which is something I omited). To do so, you can please open up FSM.cs file and add this line of code at the very start of the ‘GatherDelegates’ method just to make sure that this is not the case:

1 2 3

if ( agent == null ) { return; }

Let me know if either of the above is the case.
Thanks!

[Author]

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