Production Ready Shaders - 66 errors on import

KeyNotFoundException: The given key 'bcc5be5ab9ee6314a9a679d3e54b5a21' was not present in the dictionary.
System.Collections.Generic.Dictionary`2[TKey,TValue].get_Item (TKey key) (at <ce95f63947c64e4bbf5929ebe610c440>:0)
UnityEditor.ShaderGraph.ShaderSubGraphImporter.ContainsCircularDependency (UnityEditor.GUID assetGUID, System.Collections.Generic.Dictionary`2[TKey,TValue] dependencyMap, System.Collections.Generic.List`1[T] ancestors) (at ./Library/PackageCache/com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs:479)
UnityEditor.ShaderGraph.ShaderSubGraphImporter.ContainsCircularDependency (UnityEditor.GUID assetGUID, System.Collections.Generic.Dictionary`2[TKey,TValue] dependencyMap, System.Collections.Generic.List`1[T] ancestors) (at ./Library/PackageCache/com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs:481)
UnityEditor.ShaderGraph.ShaderSubGraphImporter.GatherDescendentsFromGraph (UnityEditor.GUID rootAssetGuid, System.Boolean& containsCircularDependency, System.Collections.Generic.HashSet`1[UnityEditor.GUID]& descendentGuids) (at ./Library/PackageCache/com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs:430)
UnityEditor.ShaderGraph.ShaderSubGraphImporter.ProcessSubGraph (UnityEditor.ShaderGraph.SubGraphAsset asset, UnityEditor.ShaderGraph.GraphData graph, UnityEditor.ShaderGraph.ShaderGraphImporter+AssetImportErrorLog importLog) (at ./Library/PackageCache/com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs:246)
UnityEditor.ShaderGraph.ShaderSubGraphImporter.OnImportAsset (UnityEditor.AssetImporters.AssetImportContext ctx) (at ./Library/PackageCache/com.unity.shadergraph/Editor/Importers/ShaderSubGraphImporter.cs:85)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) (at /Users/bokken/build/output/unity/unity/Modules/IMGUI/GUIUtility.cs:219)

Sub Graph at Assets/Samples/Shader Graph/17.0.3/Production Ready Shaders/Environment/Rock/RockMacroDetail.shadersubgraph has 5 error(s), the first is: Validation: Could not find Sub Graph asset with GUID 1586fe714d6c2424284e2ccf5296d73c.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

Shader Graph at Assets/Samples/Shader Graph/17.0.3/Production Ready Shaders/Environment/Details/Grass/GrassWindTerrainDetails.shadergraph has 8 error(s), the first is: Validation: Could not find Sub Graph asset with GUID 1586fe714d6c2424284e2ccf5296d73c.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

Problem detected while importing the Prefab file: 'Assets/Samples/Shader Graph/17.0.3/Production Ready Shaders/Prefabs/Demo.prefab'. The file might be corrupt or have a missing Variant parent or nested Prefabs. See details below. Errors: Nested Prefab problem. Missing Nested Prefab Asset: 'InfoStand (Missing Prefab with guid: 96048391e5bc0af49b1edfa6e3a2427c)' Nested Prefab problem. Missing Nested Prefab Asset: 'Turntable (Missing Prefab with guid: e4f6e5cde45e5a74889ac74289723680)'   UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)