diff --git a/backend/src/domain/adapters/csv_adapters.py b/backend/src/domain/adapters/csv_adapters.py
index e19cdaa..968d294 100644
--- a/backend/src/domain/adapters/csv_adapters.py
+++ b/backend/src/domain/adapters/csv_adapters.py
@@ -73,7 +73,7 @@ def from_dataframe(df: pd.DataFrame) -> dict[str, Course]:
 
                 instructor_names = set()
                 if instructor_name:
-                    instructor_names.add(instructor_name)
+                    instructor_names.add(str(instructor_name))
 
                 # Apply validators
                 for canonical_name, col_def in col_defs.items():
@@ -145,7 +145,9 @@ def from_dataframe(df: pd.DataFrame) -> list[Enrollment]:
                 )
 
         # Remove rows with missing required fields
-        df_clean = df_normalized.dropna(subset=["Student_PIDM", "Course_Reference_Number"])
+        df_clean = df_normalized.dropna(
+            subset=["Student_PIDM", "Course_Reference_Number"]
+        )
 
         # Build Enrollment objects
         enrollments = []
diff --git a/backend/src/services/schedule/service.py b/backend/src/services/schedule/service.py
index b09db1d..f0ec7c4 100644
--- a/backend/src/services/schedule/service.py
+++ b/backend/src/services/schedule/service.py
@@ -111,7 +111,7 @@ async def generate_schedule(
             merges = self.dataset_service.get_merges(dataset_id, user_id) or {}
 
             # 3.5 Drop zero-enrollment courses and get updated merges
-            merges = self.dataset_service.drop_zero_enrollment(dataset_id, user_id)
+            files = await self.dataset_service.drop_zero_enrollment(dataset_id, user_id)
 
             # 4. Build scheduling dataset and run algorithm
             scheduling_dataset = DatasetFactory.from_dataframes_to_scheduling_dataset(
@@ -332,6 +332,7 @@ def _build_generation_response(
         scheduling_dataset,
         conflicts_response: dict,
         parameters: dict,
+        merges: dict[str, list[str]],
     ) -> dict[str, Any]:
         """Build response for generate_schedule endpoint."""
         # Count unique students