diff --git a/Services/ImportBackgroundService.cs b/Services/ImportBackgroundService.cs
index acf058f..3c54528 100644
--- a/Services/ImportBackgroundService.cs
+++ b/Services/ImportBackgroundService.cs
@@ -596,12 +596,11 @@ public class ImportBackgroundService : BackgroundService
         });
         historyEntry.Property("RecruitImportId").CurrentValue = rec_import_id;
 
-        // get doc from minio
+        // get doc from minio (MinIOService already saves Document to its own context)
         var doc = await _minioService.UploadFileAsync(new DummyFormFile(job.ImportFile));
         var imported = new ScoreImport();
         imported.Year = rec_import_year;
         imported.RecruitImportId = rec_import_id;
-        imported.ImportFile = doc;
         imported.CreatedAt = DateTime.Now;
         imported.CreatedUserId = job.UserId ?? "";
         imported.CreatedFullName = job.FullName ?? "System Administrator";
@@ -610,8 +609,9 @@ public class ImportBackgroundService : BackgroundService
         imported.LastUpdateFullName = job.FullName ?? "System Administrator";
         imported.Scores = new List<RecruitScore>();
 
-        // Save ScoreImport parent first to get its Id
-        _context.ScoreImports.Add(imported);
+        // Save ScoreImport — use shadow FK for ImportFile to avoid re-inserting Document
+        var scoreEntry = _context.ScoreImports.Add(imported);
+        scoreEntry.Property("ImportFileId").CurrentValue = doc.Id;
         await _context.SaveChangesAsync();
         _context.ChangeTracker.Clear();