diff --git a/internal/importer/importer.go b/internal/importer/importer.go
index 4bcaeb35..2b05d87f 100644
--- a/internal/importer/importer.go
+++ b/internal/importer/importer.go
@@ -593,8 +593,18 @@ func upsertIssues(ctx context.Context, sqliteStore *sqlite.SQLiteStorage, issues
 				// Exact match (same content, same ID) - idempotent case
 				result.Unchanged++
 			} else {
-				// Same content, different ID - rename detected
-				if !opts.SkipUpdate {
+				// Same content, different ID - check if this is a rename or cross-prefix duplicate
+				existingPrefix := utils.ExtractIssuePrefix(existing.ID)
+				incomingPrefix := utils.ExtractIssuePrefix(incoming.ID)
+
+				if existingPrefix != incomingPrefix {
+					// Cross-prefix content match: same content but different projects/prefixes.
+					// This is NOT a rename - it's a duplicate from another project.
+					// Skip the incoming issue and keep the existing one unchanged.
+					// Calling handleRename would fail because CreateIssue validates prefix.
+					result.Skipped++
+				} else if !opts.SkipUpdate {
+					// Same prefix, different ID suffix - this is a true rename
 					deletedID, err := handleRename(ctx, sqliteStore, existing, incoming)
 					if err != nil {
 						return fmt.Errorf("failed to handle rename %s -> %s: %w", existing.ID, incoming.ID, err)
diff --git a/internal/importer/importer_test.go b/internal/importer/importer_test.go
index d09d0c55..ac6f6163 100644
--- a/internal/importer/importer_test.go
+++ b/internal/importer/importer_test.go
@@ -1504,3 +1504,95 @@ func TestImportOrphanSkip_CountMismatch(t *testing.T) {
 		t.Errorf("Expected 2 normal issues in database, found %d", count)
 	}
 }
+
+// TestImportCrossPrefixContentMatch tests that importing an issue with a different prefix
+// but same content hash does NOT trigger a rename operation.
+//
+// Bug scenario:
+// 1. DB has issue "alpha-abc123" with prefix "alpha" configured
+// 2. Incoming JSONL has "beta-xyz789" with same content (same hash)
+// 3. Content hash match triggers rename detection (same content, different ID)
+// 4. handleRename tries to create "beta-xyz789" which fails prefix validation
+//
+// Expected behavior: Skip the cross-prefix "rename" and keep the existing issue unchanged.
+func TestImportCrossPrefixContentMatch(t *testing.T) {
+	ctx := context.Background()
+
+	tmpDB := t.TempDir() + "/test.db"
+	store, err := sqlite.New(context.Background(), tmpDB)
+	if err != nil {
+		t.Fatalf("Failed to create store: %v", err)
+	}
+	defer store.Close()
+
+	// Configure database with "alpha" prefix
+	if err := store.SetConfig(ctx, "issue_prefix", "alpha"); err != nil {
+		t.Fatalf("Failed to set prefix: %v", err)
+	}
+
+	// Create an issue with the configured prefix
+	existingIssue := &types.Issue{
+		ID:          "alpha-abc123",
+		Title:       "Shared Content Issue",
+		Description: "This issue has content that will match a cross-prefix import",
+		Status:      types.StatusOpen,
+		Priority:    2,
+		IssueType:   types.TypeTask,
+	}
+	if err := store.CreateIssue(ctx, existingIssue, "test-setup"); err != nil {
+		t.Fatalf("Failed to create existing issue: %v", err)
+	}
+
+	// Compute the content hash of the existing issue
+	existingHash := existingIssue.ComputeContentHash()
+
+	// Create an incoming issue with DIFFERENT prefix but SAME content
+	// This simulates importing from another project with same issue content
+	incomingIssue := &types.Issue{
+		ID:          "beta-xyz789", // Different prefix!
+		Title:       "Shared Content Issue",
+		Description: "This issue has content that will match a cross-prefix import",
+		Status:      types.StatusOpen,
+		Priority:    2,
+		IssueType:   types.TypeTask,
+	}
+
+	// Verify they have the same content hash (this is what triggers the bug)
+	incomingHash := incomingIssue.ComputeContentHash()
+	if existingHash != incomingHash {
+		t.Fatalf("Test setup error: content hashes should match. existing=%s incoming=%s", existingHash, incomingHash)
+	}
+
+	// Import the cross-prefix issue with SkipPrefixValidation (simulates auto-import behavior)
+	// This should NOT fail - cross-prefix content matches should be skipped, not renamed
+	result, err := ImportIssues(ctx, tmpDB, store, []*types.Issue{incomingIssue}, Options{
+		SkipPrefixValidation: true, // Auto-import typically sets this
+	})
+	if err != nil {
+		t.Fatalf("Import should not fail for cross-prefix content match: %v", err)
+	}
+
+	// The incoming issue should be skipped (not created, not updated)
+	// because it has a different prefix than configured
+	if result.Created != 0 {
+		t.Errorf("Expected 0 created (cross-prefix should be skipped), got %d", result.Created)
+	}
+
+	// The existing issue should remain unchanged
+	retrieved, err := store.GetIssue(ctx, "alpha-abc123")
+	if err != nil {
+		t.Fatalf("Failed to retrieve existing issue: %v", err)
+	}
+	if retrieved == nil {
+		t.Fatal("Existing issue alpha-abc123 should still exist after import")
+	}
+	if retrieved.Title != "Shared Content Issue" {
+		t.Errorf("Existing issue should be unchanged, got title: %s", retrieved.Title)
+	}
+
+	// The cross-prefix issue should NOT exist in the database
+	crossPrefix, err := store.GetIssue(ctx, "beta-xyz789")
+	if err == nil && crossPrefix != nil {
+		t.Error("Cross-prefix issue beta-xyz789 should NOT be created in the database")
+	}
+}