diff --git a/src/CoreSync.Http.Client/Implementation/SyncProviderHttpClient.cs b/src/CoreSync.Http.Client/Implementation/SyncProviderHttpClient.cs
index 73fdfd9..bdfc39b 100644
--- a/src/CoreSync.Http.Client/Implementation/SyncProviderHttpClient.cs
+++ b/src/CoreSync.Http.Client/Implementation/SyncProviderHttpClient.cs
@@ -216,16 +216,17 @@ private static void ConvertJsonValueToNetObject(SyncChangeSet changeSet)
         {
             foreach (var itemValueEntry in item.Values.Where(_ => _.Key != "__OP").ToList())
             {
-                item.Values[itemValueEntry.Key].Value = itemValueEntry.Value.Value == null ? null :
-                    ConvertJsonValueToNetObject((JsonElement)itemValueEntry.Value.Value, itemValueEntry.Value.Type);
-
-                //WARN: can't convert every Id to lowercase because sqlite is case sensitive!
-                //if (itemValueEntry.Value.Value != null &&
-                //    itemValueEntry.Value.Type == SyncItemValueType.String &&
-                //    (itemValueEntry.Key == "Id" || itemValueEntry.Key.EndsWith("Id")))
-                //{
-                //    item.Values[itemValueEntry.Key].Value = itemValueEntry.Value.Value.ToString().ToLowerInvariant();
-                //}
+                var rawValue = itemValueEntry.Value.Value;
+                if (rawValue == null)
+                {
+                    item.Values[itemValueEntry.Key].Value = null;
+                }
+                else if (rawValue is JsonElement jsonElement)
+                {
+                    item.Values[itemValueEntry.Key].Value =
+                        ConvertJsonValueToNetObject(jsonElement, itemValueEntry.Value.Type);
+                }
+                // else: value is already a native .NET type — no conversion needed.
             }
         }
     }
diff --git a/src/CoreSync.Http.Server/SyncAgentController.cs b/src/CoreSync.Http.Server/SyncAgentController.cs
index 9826b54..98a889d 100644
--- a/src/CoreSync.Http.Server/SyncAgentController.cs
+++ b/src/CoreSync.Http.Server/SyncAgentController.cs
@@ -170,8 +170,18 @@ public async Task<SyncAnchor> CompleteApplyBulkChangesAsync(Guid sessionId)
             {
                 foreach (var itemValueEntry in item.Values.Where(_ => _.Key != "__OP").ToList())
                 {
-                    item.Values[itemValueEntry.Key].Value = itemValueEntry.Value.Value == null ? null :
-                        ConvertJsonElementToObject((JsonElement)itemValueEntry.Value.Value, itemValueEntry.Value.Type);
+                    var rawValue = itemValueEntry.Value.Value;
+                    if (rawValue == null)
+                    {
+                        item.Values[itemValueEntry.Key].Value = null;
+                    }
+                    else if (rawValue is JsonElement jsonElement)
+                    {
+                        item.Values[itemValueEntry.Key].Value =
+                            ConvertJsonElementToObject(jsonElement, itemValueEntry.Value.Type);
+                    }
+                    // else: value is already a native .NET type (e.g. from MessagePack deserialization
+                    // or newer System.Text.Json versions) — no conversion needed.
                 }
             }
 
diff --git a/src/CoreSync.PostgreSQL/PostgreSQLSyncProvider.cs b/src/CoreSync.PostgreSQL/PostgreSQLSyncProvider.cs
index 2d1d4a5..b3fa4e6 100644
--- a/src/CoreSync.PostgreSQL/PostgreSQLSyncProvider.cs
+++ b/src/CoreSync.PostgreSQL/PostgreSQLSyncProvider.cs
@@ -84,12 +84,18 @@ public async Task<SyncAnchor> ApplyChangesAsync([NotNull] SyncChangeSet changeSe
 
                     try
                     {
+                        // Use a savepoint so that a failed statement does not abort
+                        // the entire PostgreSQL transaction (error state 25P02).
+                        await tr.SaveAsync("sync_item", cancellationToken);
+
                         affectedRows = await cmd.ExecuteNonQueryAsync(cancellationToken);
 
                         if (affectedRows > 0)
                         {
                             _logger?.Trace($"[{_storeId}] Successfully applied {item}");
                         }
+
+                        await tr.ReleaseAsync("sync_item", cancellationToken);
                     }
                     catch (OperationCanceledException)
                     {
@@ -98,6 +104,9 @@ public async Task<SyncAnchor> ApplyChangesAsync([NotNull] SyncChangeSet changeSe
                     catch (Exception ex)
                     {
                         _logger?.Error($"Unable to {itemChangeType} item {item} to store for table {table}.{Environment.NewLine}{ex}{Environment.NewLine}Generated SQL:{Environment.NewLine}{cmd.CommandText}");
+                        // Rollback to the savepoint so the transaction can continue
+                        // processing remaining items.
+                        try { await tr.RollbackAsync("sync_item", cancellationToken); } catch { /* already rolled back */ }
                     }
 
                     if (affectedRows == 0)