diff --git a/src/Umbraco.Core/Services/Implement/ContentTypeServiceBaseOfTRepositoryTItemTService.cs b/src/Umbraco.Core/Services/Implement/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
index 480501212f..3c78644cce 100644
--- a/src/Umbraco.Core/Services/Implement/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
+++ b/src/Umbraco.Core/Services/Implement/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
@@ -67,7 +67,7 @@ namespace Umbraco.Core.Services.Implement
 
             var compositionAliases = compositionContentType.CompositionAliases();
             var compositions = allContentTypes.Where(x => compositionAliases.Any(y => x.Alias.Equals(y)));
-            var propertyTypeAliases = compositionContentType.PropertyTypes.Select(x => x.Alias.ToLowerInvariant()).ToArray();
+            var propertyTypeAliases = compositionContentType.PropertyTypes.Select(x => x.Alias).ToArray();
             var indirectReferences = allContentTypes.Where(x => x.ContentTypeComposition.Any(y => y.Id == compositionContentType.Id));
             var comparer = new DelegateEqualityComparer<IContentTypeComposition>((x, y) => x.Id == y.Id, x => x.Id);
             var dependencies = new HashSet<IContentTypeComposition>(compositions, comparer);
@@ -101,7 +101,7 @@ namespace Umbraco.Core.Services.Implement
                 if (dependency.Id == compositionContentType.Id) continue;
                 var contentTypeDependency = allContentTypes.FirstOrDefault(x => x.Alias.Equals(dependency.Alias, StringComparison.InvariantCultureIgnoreCase));
                 if (contentTypeDependency == null) continue;
-                var intersect = contentTypeDependency.PropertyTypes.Select(x => x.Alias.ToLowerInvariant()).Intersect(propertyTypeAliases).ToArray();
+                var intersect = contentTypeDependency.PropertyTypes.Select(x => x.Alias).Intersect(propertyTypeAliases, StringComparer.InvariantCultureIgnoreCase).ToArray();
                 if (intersect.Length == 0) continue;
 
                 throw new InvalidCompositionException(compositionContentType.Alias, intersect.ToArray());