diff --git a/src/Umbraco.Core/Constants-DataTypes.cs b/src/Umbraco.Core/Constants-DataTypes.cs
index d5d0e99dab..0e95e57b1b 100644
--- a/src/Umbraco.Core/Constants-DataTypes.cs
+++ b/src/Umbraco.Core/Constants-DataTypes.cs
@@ -7,7 +7,7 @@ namespace Umbraco.Core
         /// <summary>
         ///     Defines the identifiers for Umbraco data types as constants for easy centralized access/management.
         /// </summary>
-        public static class DataTypes
+        internal static class DataTypes
         {
 
             public static class ReservedPreValueKeys
diff --git a/src/Umbraco.Core/Models/DataTypeDefinitionExtensions.cs b/src/Umbraco.Core/Models/DataTypeExtensions.cs
similarity index 79%
rename from src/Umbraco.Core/Models/DataTypeDefinitionExtensions.cs
rename to src/Umbraco.Core/Models/DataTypeExtensions.cs
index 45c4420820..47702de2c5 100644
--- a/src/Umbraco.Core/Models/DataTypeDefinitionExtensions.cs
+++ b/src/Umbraco.Core/Models/DataTypeExtensions.cs
@@ -3,7 +3,7 @@ using System.Collections.Generic;
 
 namespace Umbraco.Core.Models
 {
-    public static class DataTypeDefinitionExtensions
+    internal static class DataTypeExtensions
     {
         private static readonly ISet<Guid> IdsOfBuildInDataTypes = new HashSet<Guid>()
         {
@@ -37,11 +37,19 @@ namespace Umbraco.Core.Models
         /// <summary>
         /// Returns true if this date type is build-in/default.
         /// </summary>
-        /// <param name="dataTypeDefinition">The data type definition.</param>
+        /// <param name="dataType">The data type definition.</param>
         /// <returns></returns>
-        public static bool IsBuildInDataType(this IDataTypeDefinition dataTypeDefinition)
+        public static bool IsBuildInDataType(this IDataTypeDefinition dataType)
         {
-            return IdsOfBuildInDataTypes.Contains(dataTypeDefinition.Key);
+            return IsBuildInDataType(dataType.Key);
+        }
+
+        /// <summary>
+        /// Returns true if this date type is build-in/default.
+        /// </summary>
+        public static bool IsBuildInDataType(Guid key)
+        {
+            return IdsOfBuildInDataTypes.Contains(key);
         }
     }
 }
diff --git a/src/Umbraco.Core/Services/DateTypeServiceExtensions.cs b/src/Umbraco.Core/Services/DateTypeServiceExtensions.cs
index 63006653ab..bea83558a5 100644
--- a/src/Umbraco.Core/Services/DateTypeServiceExtensions.cs
+++ b/src/Umbraco.Core/Services/DateTypeServiceExtensions.cs
@@ -1,17 +1,20 @@
 using System;
+using Umbraco.Core.Models;
 
 namespace Umbraco.Core.Services
 {
-    public static class DateTypeServiceExtensions
+    internal static class DateTypeServiceExtensions
     {
         public static bool IsDataTypeIgnoringUserStartNodes(this IDataTypeService dataTypeService, Guid key)
         {
+            if (DataTypeExtensions.IsBuildInDataType(key)) return false; //built in ones can never be ignoring start nodes
+
             var dataType = dataTypeService.GetDataTypeDefinitionById(key);
 
             if (dataType != null)
             {
                 var preValues = dataTypeService.GetPreValuesCollectionByDataTypeId(dataType.Id);
-                if (preValues.PreValuesAsDictionary.TryGetValue(
+                if (preValues.FormatAsDictionary().TryGetValue(
                     Constants.DataTypes.ReservedPreValueKeys.IgnoreUserStartNodes, out var preValue))
                     return preValue.Value.InvariantEquals("1");
             }