实体框架返回数据库中不存在的实体

Question

I got a very strange behavior with EF6. I have an entity which insertion failed, but when i enumerate the entities, the first time after that, I retrieve the entity

static async Task Debug()
{
    MyDbContext ctx = new MyDbContext();
    Category category = new Category()
    {              
        Name = "TEST INSERTION FAILED",
        Reference = "KKK",
        TranslationCategories = new List<TranslationCategory>()
        {
            new TranslationCategory()
            {                        
                //LangId = "FR", Force insertion failed
                Name= "FR translation"
            }
        }
    };
    try
    {
        ctx.Categories.Add(category);
        await ctx.SaveChangesAsync();
    }
    catch(Exception ex)
    {
        Console.WriteLine(ex.Message);
        // throw exception because "LangId" missing in Translation Category
    }
    MyDbContext ctx2 = new MyDbContext();
    foreach(var o in ctx2.Categories.ToList())
    {
        Console.WriteLine(o.Name);
        //output : "TEST INSERTION FAILED" + categories stored in DB
        // Why category "TEST INSERTION FAILED" in ctx2.Categories ?
    }
    Console.WriteLine("****************");
    foreach (var o in ctx2.Categories.ToList())
    {
        Console.WriteLine(o.Name);
        // ouput : only categories stored in DB
    }
}

Category entity generated by entity framework power tools

public partial class Category
{
    public Category()
    {
        this.Products = new List<Product>();            
        this.TranslationCategories = new List<TranslationCategory>();
    }

    public int CategoryId { get; set; }
    public Nullable<int> ParentCategoryId { get; set; }
    public string Reference { get; set; }
    public System.DateTime CreationDate { get; set; }
    public string Name { get; set; }
    public Nullable<bool> Published { get; set; }
    public string Artwork { get; set; }
    public string TypeCode { get; set; }
    public virtual ICollection<Product> Products { get; set; }        
    public virtual ICollection<TranslationCategory> TranslationCategories {get;set; }
}

Answer 1

I solved my problem. My entities and DBContext was generated using "entity framework power tools, reverse engineer code first". I have regenerated entities and dbcontext by adding Ado.net data entity model, Code First from Existing Database, and now the same code works.