Grid.SetState gives null ref with no useful stack trace

[Jason]

I'm suddenly getting null refs when I call Grid.SetState and I need more information on why.

User clicks Reset button:
await Grid.SetState(null);

And then I set a Default Sort

            var desiredState = new GridState<SearchDocumentItem>()
            {
                SortDescriptors = new List<SortDescriptor>()
                    {
                        new SortDescriptor { Member = member, SortDirection = dir }
                    }
            };

            if (Grid != null)
                await Grid.SetState(desiredState);

[Marin Bratanov]

Please add the error stack trace and when that issue happens.