unity 2018.3.6f1 with LW SRP

Hi,
When I import LW SRP Samples this package in unity 2018.3.6f1 Then below error comes.
Shader properties can't be added to this global property sheet. Trying to add _GrabTexture_HDR (type 1 count 1)
UnityEditor.AssetPreviewUpdater:CreatePreviewForAsset(Object, Object[], String)
Thanks
When I import LW SRP Samples this package in unity 2018.3.6f1 Then below error comes.
Shader properties can't be added to this global property sheet. Trying to add _GrabTexture_HDR (type 1 count 1)
UnityEditor.AssetPreviewUpdater:CreatePreviewForAsset(Object, Object[], String)
Thanks