Csharp 忽略有关生成查询表达式 EF Core 的 ThenInclude 语句

Foreword:

我有两个项目.NET Core 3.1，一个EF Core 3.1.17，另一个在5.0.10上，在这两个版本中，我都使用了Include/thenClude，方式相同，一切都很好.

Problem:

当我试图在表达式中使用ThenClude语句时，当EF生成查询时，ThenClude中的所有实体都被忽略.

这是我的表达:

var settings = await _dbRepository.GetRegionRoles(systemId)
            .Include(r => r.Region)
            .Include(sr => sr.SystemRole)
            .ThenInclude(ro => ro.Role)
            .Include(gs => gs.GroupSettings)
            .Where(w => w.GroupSettings.Any())
            .ToListAsync(cancellationToken);

EF在生成查询之前识别所有ThenClude语句(我try 在可能的地方添加更多语句，得到了相同的结果)，有跟踪日志(log):

 Compiling query expression: 
'DbSet<RegionRole>()
    .Include(x => x.SystemRole)
    .Where(w => w.SystemRole.SystemId.Equals((int)__systemId_0))
    .Include(r => r.Region)
    .Include(sr => sr.SystemRole)
    .ThenInclude(ro => ro.Role)
    .Include(gs => gs.GroupSettings)
    .Include(sr => sr.SystemRole)
    .ThenInclude(s => s.SystemCode)
    .Where(w => w.GroupSettings
        .Any())'

但生成的结果看起来像:

Generated query execution expression: 
'queryContext => new SingleQueryingEnumerable<RegionRole>(
    (RelationalQueryContext)queryContext, 
    RelationalCommandCache.SelectExpression(
        Projection Mapping:
        SELECT r.Id, r.CreatedByUser, r.CreatedDate //... and many other fields from each table
        FROM Main.RegionRole AS r
        INNER JOIN Main.SystemRole AS s ON r.SystemRoleId == s.Id
        INNER JOIN Main.Region AS r0 ON r.RegionId == r0.Id
        LEFT JOIN Main.GroupSettings AS g ON r.Id == g.RegionRoleId
        WHERE (s.SystemId == CAST(@__systemId_0) AS int)) && EXISTS (
            Projection Mapping:
            SELECT 1
            FROM Main.GroupSettings AS g0
            WHERE (r.Id != NULL) && (r.Id == g0.RegionRoleId))
        ORDER BY r.Id ASC, s.Id ASC, r0.Id ASC, g.Id ASC), 
    Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, RegionRole>, 
    K2Project.BE.DAL.Models.K2DbContext, 
    False, 
    False
)'

正如我们在这里看到的，thenClude语句中的实体"Role"在结果中缺失.

所有实体都具有导航属性，并在fluent api中进行了描述.所有表都有外键.

有一个实体"SystemRole"的示例

public class SystemRole
{        
    public Guid Id { get; set; }

    public int RoleId { get; set; }        

    #region Dependencies

    public virtual Role Role { get; set; }

    #endregion
 }

和fluent api:

public class SystemRoleEntityTypeConfiguration : IEntityTypeConfiguration<SystemRole>
{
    public void Configure(EntityTypeBuilder<SystemRole> builder)
    {
        builder.ToTable(nameof(SystemRole), DbConst.MainSchemaName);

        builder.HasKey(p => p.Id);

        builder.Property(p => p.Id)
            .ValueGeneratedOnAdd()
            .HasDefaultValueSql("NEWSEQUENTIALID()");

        builder.HasOne(p => p.Role)
            .WithMany()
            .HasForeignKey(f => f.RoleId)
            .IsRequired(true);

    }
}

Question:

在EF Core版本3.1.17和5.0.10中使用thenClude有什么区别？为什么相同的表达式适用于第一个版本，但不适用于另一个版本？也许我做错了什么，或者在更改框架版本时忘记了更改什么？

P、 在我的第二个项目中，从EF Core 5.0.10开始，所有包含Include/thenClude语句的表达式都做得很好.