diff --git a/src/IdentityServer/Extensions/HttpContextExtensions.cs b/src/IdentityServer/Extensions/HttpContextExtensions.cs
index ae104bc63..175113dd7 100644
--- a/src/IdentityServer/Extensions/HttpContextExtensions.cs
+++ b/src/IdentityServer/Extensions/HttpContextExtensions.cs
@@ -40,13 +40,12 @@ internal static async Task<string> GetIdentityServerSignoutFrameCallbackUrlAsync
         // if we have a logout message, then that take precedence over the current user
         if (logoutMessage?.ClientIds?.Any() == true)
         {
-            var clientIds = logoutMessage?.ClientIds;
+            var clientIds = logoutMessage.ClientIds;
 
             // check if current user is same, since we might have new clients (albeit unlikely)
-            if (currentSubId == logoutMessage?.SubjectId)
+            if (currentSubId == logoutMessage.SubjectId)
             {
                 clientIds = clientIds.Union(await userSession.GetClientListAsync());
-                clientIds = clientIds.Distinct();
             }
 
             endSessionMsg = new LogoutNotificationContext
diff --git a/src/IdentityServer/Services/Default/DefaultPersistedGrantService.cs b/src/IdentityServer/Services/Default/DefaultPersistedGrantService.cs
index ea053cd9d..33c3090a0 100644
--- a/src/IdentityServer/Services/Default/DefaultPersistedGrantService.cs
+++ b/src/IdentityServer/Services/Default/DefaultPersistedGrantService.cs
@@ -144,7 +144,7 @@ private IEnumerable<Grant> Join(IEnumerable<Grant> first, IEnumerable<Grant> sec
             var match = list.FirstOrDefault(x => x.ClientId == other.ClientId);
             if (match != null)
             {
-                match.Scopes = match.Scopes.Union(other.Scopes).Distinct();
+                match.Scopes = match.Scopes.Union(other.Scopes);
 
                 if (match.CreationTime > other.CreationTime)
                 {