EF Core 7多Include查询引发Departures实体重复枚举问题

我们有对应的数据库架构，测试场景为查找Connection并验证其关联所有Departures的Id唯一性。EF Core 6中一切正常，每个Departure条目仅出现一次；但升级至EF Core 7（7.0.0或7.0.2）后，部分Departures重复出现，导致验证Id唯一性的测试失败。

测试代码 #

// ...preparing DI
this.lines = scope.ServiceProvider.GetRequiredService<ILinesRepository>();
lines.Load(); // heavy task loading the data into memory for about 2 minutes (i know it's not really good but it's not my code...)
var connection = lines.GetConnection(lineNumber, connectionNumber); // filtering the data loaded in previous step
var groups = connection.Departures.GroupBy(d => d.Id); // finding the number of distinct IDs
Assert.Equal(groups.Count(), connection.Departures.Count);

lines.Load(DateTime? forDate = null)方法代码 #

var date = forDate ?? DateTime.Today;
// ... fetching some other data
_departures = DeparturesSet
     .Include(d => d.TariffStation)
          .ThenInclude(ts => ts.BackwardPlatform)
     .Include(d => d.TariffStation)
          .ThenInclude(ts => ts.ForwardPlatform)
     .Include(d => d.TariffStation)
          .ThenInclude(ts => ts.Station)
     .Include(d => d.Connection)
          .ThenInclude(l => l.Line)
                .ThenInclude(l => l.Validity)
     .Where(d => !d.Connection.Line.ValidTo.HasValue || d.Connection.Line.ValidTo.Value >= date)
     .AsSplitQuery()            
     .ToArray();
// ... fetching some other data

ConnectionEntity? GetConnection(long lineNumber, int connectionNumber)方法代码 #

_departures?.FirstOrDefault(d =>
            d.Connection.Line.IsValid(DateTime.Now) && d.Connection.Number == connectionNumber && d.Connection.Line.Number == lineNumber)?.Connection;

排查情况 #

尝试注释掉_departures查询中的不同部分，仅保留Connection和Line的Include（否则测试会因空引用失败）。只要查询中包含至少一个.Include(d => d.TariffStation)（即使没有ThenInclude部分），测试就会失败。

看起来被Include的TariffStation还会获取所有关联的Departures，但这在实体类和映射中均未定义。

TariffStationEntity与DepartureEntity的关联配置（b为DepartureEntity） #

builder.HasOne(b => b.TariffStation)
   .WithMany()
   .HasForeignKey(b => b.TariffStationId)
   .OnDelete(DeleteBehavior.Restrict);

内容的提问来源于stack exchange，提问作者Nomen