diff --git a/src/Hl7.Fhir.Conformance/Specification/Snapshot/SnapshotGeneratorExtensions.cs b/src/Hl7.Fhir.Conformance/Specification/Snapshot/SnapshotGeneratorExtensions.cs
index b1b8688e5c..278a121572 100644
--- a/src/Hl7.Fhir.Conformance/Specification/Snapshot/SnapshotGeneratorExtensions.cs
+++ b/src/Hl7.Fhir.Conformance/Specification/Snapshot/SnapshotGeneratorExtensions.cs
@@ -7,9 +7,8 @@
  */
 
 using Hl7.Fhir.Model;
-using Hl7.Fhir.Support;
+using Hl7.Fhir.Rest;
 using Hl7.Fhir.Utility;
-using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -74,6 +73,47 @@ public static void RemoveAllConstrainedByDiffExtensions<T>(this IEnumerable<T> e
             }
         }
 
+
+        internal static void RemoveAllNonInheritableExtensions(this Element element)
+        {
+            if (element == null) { throw Error.ArgumentNull(nameof(element)); }
+            element.RemoveNonInheritableExtensions();
+            foreach (var child in element.Children.OfType<Element>())
+            {
+                child.RemoveAllNonInheritableExtensions();
+            }
+        }
+
+        internal static void RemoveNonInheritableExtensions(this IExtendable element)
+        {
+            if (element == null) { throw Error.ArgumentNull(nameof(element)); }
+            foreach (var ext in _nonInheritableExtensions)
+            {
+                element.RemoveExtension(ext);
+            }
+        }
+
+        private static readonly List<string> _nonInheritableExtensions = [
+         ResourceIdentity.CORE_BASE_URL + "elementdefinition-isCommonBinding",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-fmm",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-fmm-no-warnings",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-hierarchy",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-interface",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-normative-version",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-applicable-version",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-category",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-codegen-super",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-security-category",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-standards-status",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-summary",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-wg",
+         ResourceIdentity.CORE_BASE_URL + "replaces",
+         ResourceIdentity.CORE_BASE_URL + "resource-approvalDate",
+         ResourceIdentity.CORE_BASE_URL + "resource-effectivePeriod",
+         ResourceIdentity.CORE_BASE_URL + "resource-lastReviewDate",
+         CONSTRAINED_BY_DIFF_EXT //this is our own extension to define differences compared to the base, this can't be inherited from the base profile
+        ];
+
         // ========== For internal use only ==========
         // [WMR 20170209] OBSOLETE
 #if false
diff --git a/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGenerator.cs b/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGenerator.cs
index 662f8531ea..01b7264441 100644
--- a/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGenerator.cs
+++ b/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGenerator.cs
@@ -399,7 +399,8 @@ private async Tasks.Task<List<ElementDefinition>> generate(StructureDefinition s
 
                 // [WMR 20170208] Moved to *AFTER* ensureBaseComponents - emits annotations...
                 // [WMR 20160915] Derived profiles should never inherit the ChangedByDiff extension from the base structure
-                snapshot.Element.RemoveAllConstrainedByDiffExtensions();
+                // Also remove core extensions that are not supposed to be inherited by derived profiles
+                snapshot.RemoveAllNonInheritableExtensions();
                 snapshot.Element.RemoveAllConstrainedByDiffAnnotations();
 
                 // Notify observers
diff --git a/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGeneratorExtensions.cs b/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGeneratorExtensions.cs
index 2c13de5f28..9663245562 100644
--- a/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGeneratorExtensions.cs
+++ b/src/Hl7.Fhir.STU3/Specification/Snapshot/SnapshotGeneratorExtensions.cs
@@ -7,9 +7,8 @@
  */
 
 using Hl7.Fhir.Model;
-using Hl7.Fhir.Support;
+using Hl7.Fhir.Rest;
 using Hl7.Fhir.Utility;
-using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -73,6 +72,47 @@ public static void RemoveAllConstrainedByDiffExtensions<T>(this IEnumerable<T> e
             }
         }
 
+        internal static void RemoveAllNonInheritableExtensions(this Element element)
+        {
+            if (element == null) { throw Error.ArgumentNull(nameof(element)); }
+            element.RemoveNonInheritableExtensions();
+            foreach (var child in element.Children.OfType<Element>())
+            {
+                child.RemoveAllNonInheritableExtensions();
+            }
+        }
+
+        internal static void RemoveNonInheritableExtensions(this IExtendable element)
+        {
+            if (element == null) { throw Error.ArgumentNull(nameof(element)); }
+            foreach (var ext in _nonInheritableExtensions)
+            {
+                element.RemoveExtension(ext);
+            }
+        }
+
+        private static readonly List<string> _nonInheritableExtensions = [
+         ResourceIdentity.CORE_BASE_URL + "elementdefinition-isCommonBinding",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-fmm",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-fmm-no-warnings",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-hierarchy",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-interface",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-normative-version",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-applicable-version",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-category",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-codegen-super",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-security-category",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-standards-status",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-summary",
+         ResourceIdentity.CORE_BASE_URL + "structuredefinition-wg",
+         ResourceIdentity.CORE_BASE_URL + "replaces",
+         ResourceIdentity.CORE_BASE_URL + "resource-approvalDate",
+         ResourceIdentity.CORE_BASE_URL + "resource-effectivePeriod",
+         ResourceIdentity.CORE_BASE_URL + "resource-lastReviewDate",
+         CONSTRAINED_BY_DIFF_EXT //this is our own extension to define differences compared to the base, this can't be inherited from the base profile
+        ];
+
+
         // ========== For internal use only ==========
         // [WMR 20170209] OBSOLETE
 #if false
diff --git a/src/Hl7.Fhir.Specification.STU3.Tests/Snapshot/SnapshotGeneratorTest.cs b/src/Hl7.Fhir.Specification.STU3.Tests/Snapshot/SnapshotGeneratorTest.cs
index 04c280575f..ba3bc9c1e3 100644
--- a/src/Hl7.Fhir.Specification.STU3.Tests/Snapshot/SnapshotGeneratorTest.cs
+++ b/src/Hl7.Fhir.Specification.STU3.Tests/Snapshot/SnapshotGeneratorTest.cs
@@ -21,8 +21,8 @@
 using Hl7.Fhir.Support;
 using Hl7.Fhir.Utility;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using System;
 using NSubstitute;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
@@ -2433,8 +2433,8 @@ private static bool isAlmostExactly(ElementDefinition elem, ElementDefinition ba
             }
 
             // Also ignore any Changed extensions on base and diff
-            elemClone.RemoveAllConstrainedByDiffExtensions();
-            baseClone.RemoveAllConstrainedByDiffExtensions();
+            elemClone.RemoveAllNonInheritableExtensions();
+            baseClone.RemoveAllNonInheritableExtensions();
             elemClone.RemoveAllConstrainedByDiffAnnotations();
             baseClone.RemoveAllConstrainedByDiffAnnotations();
 
diff --git a/src/Hl7.Fhir.Specification.Shared.Tests/Snapshot/SnapshotGeneratorTest.cs b/src/Hl7.Fhir.Specification.Shared.Tests/Snapshot/SnapshotGeneratorTest.cs
index 48fb3b9acd..8ff23d24b7 100644
--- a/src/Hl7.Fhir.Specification.Shared.Tests/Snapshot/SnapshotGeneratorTest.cs
+++ b/src/Hl7.Fhir.Specification.Shared.Tests/Snapshot/SnapshotGeneratorTest.cs
@@ -10060,6 +10060,37 @@ private StructureDefinition createVeryNestedExtension()
         }
 
 
+        [TestMethod]
+        public void RemoveNonInhertitableSnapshotsTest()
+        {
+            var profile = new StructureDefinition
+            {
+                Url = "http://fire.ly/StructureDefinition/example",
+                Snapshot = new()
+                {
+                    Element = new() {
+                        new("Example")
+                        {
+                            Binding = new()
+                            {
+                                Strength = BindingStrength.Required,
+                                ValueSet = "http://fire.ly/ValueSet/example"
+                            }
+                        },
+                    }
+                }
+            };
+
+            profile.Snapshot.Element[0].AddExtension(ResourceIdentity.CORE_BASE_URL + "structuredefinition-hierarchy", new FhirString("foo"));
+            profile.Snapshot.Element[0].Binding.AddExtension(ResourceIdentity.CORE_BASE_URL + "elementdefinition-isCommonBinding", new FhirBoolean(true));
+
+            profile.Snapshot.RemoveAllNonInheritableExtensions();
+
+            profile.Snapshot.Element[0].Extension.Should().BeEmpty();
+            profile.Snapshot.Element[0].Binding.Extension.Should().BeEmpty();
+        }
+
+
         [TestMethod]
         public async Tasks.Task TestNewR5Elements()
         {