let’s say that i have entity(root entity) that has nested 1:N entities

public class RootEntity{
  private String name;
  private List<ChildEntity> child; 
}

public class ChildEntity{
  private String cname;
  private List<CChildEntity> cchild;
}

public class CChildEntity{
  private String ccname;
}

public record RootDto(
  private String name,
  private List<ChildDto> child
){}

public record ChildDto(
  private String cname,
  private List<CChildDto> cchild
){}

public record CChildDto(
  private String ccname
){}

and trying to retrieve all with QueryDSL

@Transactional
public List<RootDto> get(){
  JPAQuery<RootDto> query = queryFactory
    .selectDistinct(Projections.constructor(ResponseDto.class, RootEntity))
    .from(root)
    .leftJoin(root.childs, child)
    .leftJoin(child.cchilds, cchild)

  List<RootDto> content = query.fetch()
  return content;
}

Above execution causes N+1 problem. which i did not expected/
But below does not have N+1 problem. why is that?
Those two are looks like same operation to me.

@Transactional
public List<RootDto> get(){
  JPAQuery<RootDto> query = queryFactory
    .selectDistinct(root)
    .from(root)
    .leftJoin(root.childs, child)
    .leftJoin(child.cchilds, cchild)

  List<RootDto> content = query.fetch().stream().map(RootDto::new).toList();
  return content;
}

and if Projections.contsructor does not support EntityManager to initialize those entity via Dtos, why is that? and how could that be possible? (again, looks similar to me)