TextMesh Pro Got a MissingReferenceException error on TextMeshPro latest plugin from asset store

I opened "12 - Link Example" scene and in Wrapping&Overflow tried to set the Overflow to Scroll rect and while setting it back to Overflow showed this error in unity editor. The error doesn't create any problem but I thought I should let you guys know.

AssetStore version 1.0.56.0b3

MissingReferenceException: The object of type 'Material' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
TMPro.TextMeshProUGUI.GenerateTextMesh ()
TMPro.TextMeshProUGUI.OnPreRenderCanvas ()
TMPro.TextMeshProUGUI.Rebuild (CanvasUpdate update)
UnityEngine.UI.CanvasUpdateRegistry.PerformUpdate () (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/CanvasUpdateRegistry.cs:150)
UnityEngine.Canvas:SendWillRenderCanvases()

 

I'll take a look this afternoon and provide feedback once I have more information.