diff --git a/CHANGES.md b/CHANGES.md
index fd4b1da80c..a538b2ddfb 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -261,6 +261,8 @@ To be released.
  -  (Libplanet.RocksDBStore) Fixed a bug where `RocksDBStore.GetBlock<T>()`
     and `RocksDBStore.GetTransaction<T>()` handn't returned expected values
     in multithreading environment.  [[#1339], [#1342]]
+ -  Fixed a bug where chain synchronization had been incorrectly updated with
+    an improper chain.  [[#1349], [#1350]]
  -  Fixed a bug where `Swarm<T>` hadn't respond immediately under load.
     [[#1360]]
 
@@ -321,6 +323,8 @@ To be released.
 [#1342]: https://github.com/planetarium/libplanet/pull/1342
 [#1343]: https://github.com/planetarium/libplanet/pull/1343
 [#1348]: https://github.com/planetarium/libplanet/pull/1348
+[#1349]: https://github.com/planetarium/libplanet/issues/1349
+[#1350]: https://github.com/planetarium/libplanet/pull/1350
 [#1351]: https://github.com/planetarium/libplanet/pull/1351
 [#1360]: https://github.com/planetarium/libplanet/pull/1360
 
diff --git a/Libplanet/Net/Swarm.BlockSync.cs b/Libplanet/Net/Swarm.BlockSync.cs
index 335934c6c7..d76a14c90c 100644
--- a/Libplanet/Net/Swarm.BlockSync.cs
+++ b/Libplanet/Net/Swarm.BlockSync.cs
@@ -172,14 +172,9 @@ CancellationToken cancellationToken
                 var canonComparer = BlockChain.Policy.CanonicalChainComparer;
                 if (synced is { } syncedB
                     && !syncedB.Id.Equals(blockChain?.Id)
-                    && (!(blockChain.Tip is { } tip && syncedB.Tip is { } syncedTip)
-                        || canonComparer.Compare(
-                            blockChain.PerceiveBlock(tip),
-                            blockChain.PerceiveBlock(
-                                syncedTip,
-                                syncedB.PerceiveBlock(syncedTip).PerceivedTime
-                            )
-                        ) < 0
+                    && (canonComparer.Compare(
+                        blockChain.PerceiveBlock(blockChain.Tip),
+                        blockChain.PerceiveBlock(syncedB.Tip)) < 0
                     )
                 )
                 {