There are two ways to trigger a NullReferenceException with Texture2DArray:

# Opening a scene that uses a Texture2DArray. Find the Draw Call in the tree and clicking the texture icon in the Texture foldout.
# Finding a Texture2DArray in the project. Click it so it should appear in an inspector.

{code:java}
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Texture2DArrayPreview.OnPreviewGUI (UnityEngine.Texture t, UnityEngine.Rect r, UnityEngine.GUIStyle background, System.Single exposure, UnityEditor.TextureInspector+PreviewMode previewMode, System.Single mipLevel) (at /opt/UnitySrc/unity/Editor/Mono/Inspector/Texture2DArrayPreview.cs:103)
{code}