diff --git a/pkg/channels/base.go b/pkg/channels/base.go
index bd4ced849..14063db21 100644
--- a/pkg/channels/base.go
+++ b/pkg/channels/base.go
@@ -259,7 +259,11 @@ func (c *BaseChannel) HandleMessage(
 	}
 	if sender.CanonicalID != "" || sender.PlatformID != "" {
 		if !c.IsAllowedSender(sender) {
-			return
+			// Backward-compatible fallback for channels that already resolved sender
+			// via a legacy identifier before publishing.
+			if !c.IsAllowed(senderID) {
+				return
+			}
 		}
 	} else {
 		if !c.IsAllowed(senderID) {
diff --git a/pkg/channels/qq/qq.go b/pkg/channels/qq/qq.go
index 004b8c420..19ee09b1e 100644
--- a/pkg/channels/qq/qq.go
+++ b/pkg/channels/qq/qq.go
@@ -130,7 +130,9 @@ func (c *QQChannel) resolveAllowedSender(primaryOpenID, legacyID string) (bus.Se
 			PlatformID: legacyID,
 		}
 		if c.IsAllowedSender(legacy) {
-			return legacy, true, true
+			// Keep openid/canonical sender identity in published messages,
+			// while recording that allow_from matched via legacy fallback.
+			return primary, true, true
 		}
 	}
 
@@ -781,10 +783,15 @@ func (c *QQChannel) handleC2CMessage() event.C2CMessageEventHandler {
 			metadata["legacy_account_id"] = legacyAuthorID
 		}
 
+		allowCheckSenderID := senderID
+		if usedLegacyFallback && legacyAuthorID != "" {
+			allowCheckSenderID = legacyAuthorID
+		}
+
 		c.HandleMessage(c.ctx,
 			bus.Peer{Kind: "direct", ID: chatID},
 			data.ID,
-			senderID,
+			allowCheckSenderID,
 			chatID,
 			content,
 			mediaPaths,
@@ -897,10 +904,15 @@ func (c *QQChannel) handleGroupATMessage() event.GroupATMessageEventHandler {
 			metadata["legacy_account_id"] = legacyMemberID
 		}
 
+		allowCheckSenderID := senderID
+		if usedLegacyFallback && legacyMemberID != "" {
+			allowCheckSenderID = legacyMemberID
+		}
+
 		c.HandleMessage(c.ctx,
 			bus.Peer{Kind: "group", ID: chatID},
 			data.ID,
-			senderID,
+			allowCheckSenderID,
 			chatID,
 			content,
 			mediaPaths,
diff --git a/pkg/channels/qq/qq_test.go b/pkg/channels/qq/qq_test.go
index 5ef2b403b..cd570bdc0 100644
--- a/pkg/channels/qq/qq_test.go
+++ b/pkg/channels/qq/qq_test.go
@@ -115,8 +115,14 @@ func TestHandleC2CMessage_AllowListFallsBackToLegacyID(t *testing.T) {
 	}
 
 	inbound := waitInboundMessage(t, messageBus)
-	if inbound.SenderID != "user-openid-123" {
-		t.Fatalf("inbound.SenderID = %q, want %q", inbound.SenderID, "user-openid-123")
+	if inbound.SenderID != "qq:user-openid-123" {
+		t.Fatalf("inbound.SenderID = %q, want %q", inbound.SenderID, "qq:user-openid-123")
+	}
+	if inbound.Sender.PlatformID != "user-openid-123" {
+		t.Fatalf("inbound.Sender.PlatformID = %q, want %q", inbound.Sender.PlatformID, "user-openid-123")
+	}
+	if inbound.Sender.CanonicalID != "qq:user-openid-123" {
+		t.Fatalf("inbound.Sender.CanonicalID = %q, want %q", inbound.Sender.CanonicalID, "qq:user-openid-123")
 	}
 	if inbound.Metadata["account_id"] != "user-openid-123" {
 		t.Fatalf("account_id metadata = %q, want %q", inbound.Metadata["account_id"], "user-openid-123")
@@ -183,8 +189,14 @@ func TestHandleGroupATMessage_AllowListFallsBackToLegacyMemberID(t *testing.T) {
 	}
 
 	inbound := waitInboundMessage(t, messageBus)
-	if inbound.SenderID != "member-openid-xyz" {
-		t.Fatalf("inbound.SenderID = %q, want %q", inbound.SenderID, "member-openid-xyz")
+	if inbound.SenderID != "qq:member-openid-xyz" {
+		t.Fatalf("inbound.SenderID = %q, want %q", inbound.SenderID, "qq:member-openid-xyz")
+	}
+	if inbound.Sender.PlatformID != "member-openid-xyz" {
+		t.Fatalf("inbound.Sender.PlatformID = %q, want %q", inbound.Sender.PlatformID, "member-openid-xyz")
+	}
+	if inbound.Sender.CanonicalID != "qq:member-openid-xyz" {
+		t.Fatalf("inbound.Sender.CanonicalID = %q, want %q", inbound.Sender.CanonicalID, "qq:member-openid-xyz")
 	}
 	if inbound.Metadata["account_id"] != "member-openid-xyz" {
 		t.Fatalf("account_id metadata = %q, want %q", inbound.Metadata["account_id"], "member-openid-xyz")