EF Core bug with null check in nested projection

Program.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;

namespace EfCoreBug
{
    class Program
    {
        static async Task Main(string[] args)
        {
            using (var context = new ClientContext())
            {
                //context.Database.EnsureDeleted();
                context.Database.EnsureCreated();

                var query1 = context.Ads.Select(dtoAd => new AdDto()
                {
                    Offers = dtoAd.Offers.Select(dtoOffer => new
                    {
                        __LastAction = dtoOffer.Actions.OrderByDescending(a => a.TimeCreatedUtc).FirstOrDefault(),
                        Id = dtoOffer.Id
                    })
                    .Select(dtoLet => new OfferDto()
                    {
                        Id = dtoLet.Id,
                        LastAction = dtoLet.__LastAction == null ? null : new OfferActionDto()
                        {
                            Action = dtoLet.__LastAction.Action,
                            TimeCreatedUtc = dtoLet.__LastAction.TimeCreatedUtc,
                            AnyEstablished = dtoLet.__LastAction.Offer.Actions.Any(a => a.Action == OfferActions.Established)
                        }
                    })
                    .ToList()
                });

                var query2 = context.Offers.Select(dtoOffer => new
                {
                    __LastAction = dtoOffer.Actions.OrderByDescending(a => a.TimeCreatedUtc).FirstOrDefault(),
                    Id = dtoOffer.Id
                })
                .Select(dtoLet => new OfferDto()
                {
                    Id = dtoLet.Id,
                    LastAction = dtoLet.__LastAction == null ? null : new OfferActionDto()
                    {
                        Action = dtoLet.__LastAction.Action,
                        TimeCreatedUtc = dtoLet.__LastAction.TimeCreatedUtc,
                        // IF THIS LINE IS COMMENTED OUT, QUERY WILL WORK IN BOTH SQL AND INMEMORY
                        AnyEstablished = dtoLet.__LastAction.Offer.Actions.Any(a => a.Action == OfferActions.Established)
                    }
                });

                // INMEMORY: System.ArgumentNullException: 'Value cannot be null.'
                // SQL (without QueryClientEvaluationWarning): System.InvalidOperationException: 'No mapping to a relational type can be found for the CLR type 'object'.'
                // SQL (with QueryClientEvaluationWarning): System.InvalidOperationException: 'Error generated for warning 'Microsoft.EntityFrameworkCore.Query.QueryClientEvaluationWarning: The LINQ expression 'where (Convert([a].Action, Int32) == 1)' could not be translated and will be evaluated locally.'. 
                //await query1.ToListAsync();

                // INMEMORY: System.ArgumentNullException: 'Value cannot be null.'
                // SQL (without QueryClientEvaluationWarning): System.ArgumentNullException: 'Value cannot be null.'
                // SQL (with QueryClientEvaluationWarning): System.InvalidOperationException: 'Error generated for warning 'Microsoft.EntityFrameworkCore.Query.QueryClientEvaluationWarning: The LINQ expression 'where (Convert([a].Action, Int32) == 1)' could not be translated and will be evaluated locally.'. 
                await query2.ToListAsync();
            }
        }

        public class Ad
        {
            public int Id { get; set; }

            // navigation properties
            public ICollection<Offer> Offers { get; set; }
        }

        public class AdDto
        {
            public ICollection<OfferDto> Offers { get; set; }
        }

        public class Offer
        {
            public int Id { get; set; }

            [Required]
            public Ad Ad { get; set; }
            public int AdId { get; set; }

            // navigation properties
            public ICollection<OfferAction> Actions { get; set; }
        }

        public enum OfferActions : int
        {
            Established = 1
        }

        public class OfferAction
        {
            public int Id { get; set; }

            [Required]
            public Offer Offer { get; set; }
            public int OfferId { get; set; }

            [Required]
            public DateTime TimeCreatedUtc { get; set; }

            [Required]
            public OfferActions Action { get; set; }
        }

        public class OfferDto
        {
            public int Id { get; set; }

            public OfferActionDto LastAction { get; set; }
        }

        public class OfferActionDto
        {
            public DateTime TimeCreatedUtc { get; set; }
            public OfferActions Action { get; set; }
            public bool AnyEstablished { get; set; }
        }

        class ClientContext : DbContext
        {
            protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
            {
                // TO USE SQL
                optionsBuilder
                    .UseSqlServer("Server=(localdb)\\mssqllocaldb;Database=EfCoreBug;Trusted_Connection=True;MultipleActiveResultSets=true;Connect Timeout=30")
                    .ConfigureWarnings(warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
                // TO USE INMEMORY
                //optionsBuilder
                //    .UseInMemoryDatabase(Guid.NewGuid().ToString())
                //    .ConfigureWarnings(warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
            }

            protected override void OnModelCreating(ModelBuilder builder)
            {
                base.OnModelCreating(builder);

                builder.Entity<Ad>().HasData(new Ad
                {
                    Id = 1
                });
                builder.Entity<Offer>().HasData(new Offer
                {
                    Id = 1,
                    AdId = 1
                });
                builder.Entity<OfferAction>().HasData(new OfferAction()
                {
                    Id = 1,
                    OfferId = 1,
                    Action = Program.OfferActions.Established,
                    TimeCreatedUtc = DateTime.UtcNow
                });
            }

            public DbSet<Ad> Ads { get; set; }
            public DbSet<Offer> Offers { get; set; }
            public DbSet<OfferAction> OfferActions { get; set; }
        }
    }
}

Project.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="AutoMapper" Version="7.0.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="2.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.2" />
  </ItemGroup>

</Project>

Thanks so much for answer me :)
Have a great day :D!