diff --git a/compactor/src/parquet_file_combining.rs b/compactor/src/parquet_file_combining.rs
index 532a5cf3d5..7172c5a822 100644
--- a/compactor/src/parquet_file_combining.rs
+++ b/compactor/src/parquet_file_combining.rs
@@ -374,6 +374,7 @@ mod tests {
         .join("\n");
         let builder = TestParquetFileBuilder::default()
             .with_line_protocol(&lp)
+            .with_max_seq(20) // This should be irrelevant because this is a level 1 file
             .with_compaction_level(CompactionLevel::FileNonOverlapped); // Prev compaction
         let level_1_file = partition.create_parquet_file(builder).await;
 
@@ -399,18 +400,30 @@ mod tests {
             .with_max_seq(2);
         let level_0_max_seq_2 = partition.create_parquet_file(builder).await;
 
+        let lp = vec![
+            "table,tag1=VT field_int=88i 10000", // will be deduplicated with level_0_max_seq_1
+            "table,tag1=OR field_int=99i 12000",
+        ]
+        .join("\n");
+        let builder = TestParquetFileBuilder::default()
+            .with_line_protocol(&lp)
+            .with_max_seq(5) // This should be irrelevant because this is a level 1 file
+            .with_compaction_level(CompactionLevel::FileNonOverlapped); // Prev compaction
+        let level_1_with_duplicates = partition.create_parquet_file(builder).await;
+
         let lp = vec!["table,tag2=OH,tag3=21 field_int=21i 36000"].join("\n");
         let builder = TestParquetFileBuilder::default()
             .with_line_protocol(&lp)
             .with_file_size_bytes(40 * 1024 * 1024); // Really large file
         let large_file = partition.create_parquet_file(builder).await;
 
-        // Order here is important! The Level 1 files are first, then Level 0 files in max seq num
-        // ascending order, as filter_parquet_files would create them
+        // Order here isn't relevant; the chunk order should ensure the level 1 files are ordered
+        // first, then the other files by max seq num.
         let parquet_files = vec![
-            level_1_file.parquet_file,
-            level_0_max_seq_1.parquet_file,
             level_0_max_seq_2.parquet_file,
+            level_1_with_duplicates.parquet_file,
+            level_0_max_seq_1.parquet_file,
+            level_1_file.parquet_file,
             large_file.parquet_file,
         ];
 
@@ -480,7 +493,7 @@ mod tests {
         } = test_setup().await;
 
         compact_parquet_files(
-            parquet_files.into_iter().take(3).collect(),
+            parquet_files.into_iter().take(4).collect(),
             &candidate_partition,
             Arc::clone(&catalog.catalog),
             ParquetStorage::new(Arc::clone(&catalog.object_store)),
@@ -501,13 +514,13 @@ mod tests {
         // 1 large file not included in compaction
         assert_eq!(
             (files[0].id.get(), files[0].compaction_level),
-            (4, CompactionLevel::Initial)
+            (5, CompactionLevel::Initial)
         );
         // 1 newly created CompactionLevel::FileNonOverlapped file as the result of
         // compaction
         assert_eq!(
             (files[1].id.get(), files[1].compaction_level),
-            (5, CompactionLevel::FileNonOverlapped)
+            (6, CompactionLevel::FileNonOverlapped)
         );
 
         // ------------------------------------------------
@@ -528,6 +541,7 @@ mod tests {
                 "| 21        |      | OH   | 21   | 1970-01-01T00:00:00.000036Z |",
                 "| 270       | UT   |      |      | 1970-01-01T00:00:00.000025Z |",
                 "| 70        | UT   |      |      | 1970-01-01T00:00:00.000020Z |",
+                "| 99        | OR   |      |      | 1970-01-01T00:00:00.000012Z |",
                 "+-----------+------+------+------+-----------------------------+",
             ],
             &batches