NullReferenceException Serialization.AstarSerializer.SerializeNodes

NullReferenceException: Object reference not set to an instance of an object Pathfinding.Serialization.AstarSerializer.SerializeNodes (Int32 index) (at Assets/Plugins/AstarPathfindingProject/Core/Serialization/JsonSerializer.cs:203) Pathfinding.Serialization.AstarSerializer.SerializeNodes () (at Assets/Plugins/AstarPathfindingProject/Core/Serialization/JsonSerializer.cs:184) Pathfinding.AstarData.SerializeGraphsPart (Pathfinding.Serialization.AstarSerializer sr) (at Assets/Plugins/AstarPathfindingProject/Core/AstarData.cs:283) Pathfinding.AstarData.SerializeGraphs (Pathfinding.Serialization.SerializeSettings settings, System.UInt32& checksum) (at Assets/Plugins/AstarPathfindingProject/Core/AstarData.cs:267) Pathfinding.AstarData.SerializeGraphs (Pathfinding.Serialization.SerializeSettings settings) (at Assets/Plugins/AstarPathfindingProject/Core/AstarData.cs:257) Pathfinding.AstarData.SaveCacheData (Pathfinding.Serialization.SerializeSettings settings) (at Assets/Plugins/AstarPathfindingProject/Core/AstarData.cs:241) AstarPathEditor.DrawSerializationSettings () (at Assets/AstarPathfindingEditor/Editor/AstarPathEditor.cs:1544) AstarPathEditor.DrawMainArea () (at Assets/AstarPathfindingEditor/Editor/AstarPathEditor.cs:822) AstarPathEditor.OnInspectorGUI () (at Assets/AstarPathfindingEditor/Editor/AstarPathEditor.cs:426) UnityEditor.InspectorWindow.DrawEditors (Boolean isRepaintEvent, UnityEditor.Editor[] editors, Boolean eyeDropperDirty) (at C:/BuildAgent/work/7535de4ca26c26ac/Editor/Mono/Inspector/InspectorWindow.cs:863) UnityEditor.DockArea:OnGUI()

On development pro version 3.2.6 , also happens in 3.2.5
When generating chache with save node data checked. If save node data is not checked there is no error, but ofcource I get errors when trying to find a path since there is no node data.

Windows 7, grid graph

It seems I was able to patch this issue by adding:

if(graphs[i] == null) continue;

to lines 183, 191 and 246 in JsonSerializer.cs.

Hopefully this may help someone else.