Coroutine resetting a FOR iterator.

Hello everybody,

I have a question. I am performing a repeat loop with a FOR. In this "FOR", I'm calling a "YIELD RETURN NULL" in each repetition of the loop. The problem is that my iterator is always 0, and the loop eventually becomes infinite!

I recorded a video with the problem: VIDEO

And the code:

     IEnumerator ProcessSaveGame () {
         _isSaving = true;
         Data = new PlayerData();
 
         var buildings = StructuresManager.GetBuildingList();
         if (buildings != null && buildings.Count > 0)
         {
             yield return StartCoroutine(SaveBuildings(buildings));
         }
 
         BinaryFormatter bf = new BinaryFormatter();
         FileStream file = File.Create(Application.persistentDataPath + "/gameData001.dat");
         
         bf.Serialize(file, Data);
         file.Close();
 
         _isSaving = false;
     }
 
     IEnumerator SaveBuildings (List<Building> buildings) {
         for (int i = 0; i < buildings.Count; i++)
         {
             AddBuildingData(buildings[i]);
 
             yield return null;
         }
     }