Problem when mapping DateTime

AutoMapper.cs

static void Main(string[] args)
{
    var config = new MapperConfiguration(cfg =>
        {
            cfg.CreateMap<Period1, Period2>()
                    .ForMember(x => x.StartDate, o => o.MapFrom(p => p.Start))
                    .ForMember(x => x.EndDate, o => o.MapFrom(p => p.End));
        });

    config.AssertConfigurationIsValid();

    var mapper = config.CreateMapper();

    var p1 = new Period1
    {
        Start = DateTime.UtcNow.AddDays(-2),
        End = DateTime.UtcNow
    };

    var p2 = mapper.Map<Period2>(p1);

    if(p1.Start == p2.StartDate)
    {
      //Yay, success!
    }
    else
      throw new Exception($"{p1.Start} != {p2.StartDate}");
}

public class Period1 
{
    public Period1()
    { }
    public Period1(DateTime start, DateTime end)
    {
        Start = start;
        End = end;
    }

    public DateTime Start { get; set; }
    public DateTime End { get; set; }
}

public class Period2
{
    public Period2()
    {
    }

    public Period2(DateTime startDate, DateTime endDate)
    {
        StartDate = startDate;
        EndDate = endDate;
    }

    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
}