Why does Odata can't parse JSON when using Extend?

Question

I'm using OData v4 in my project Web Api (.Net Core 3.1). I'm using Devart Linqconnect to generate my model. When I want to use "Extend" I'm getting message "can't parse JSON. Raw value". "Select" and "Filter" working good. I'm wondering why "Extend" not working properly.

[EnableQuery(PageSize = 2)]
[HttpGet]
public IActionResult Get(ODataQueryOptions<Tasks_Object> query)
{

var items = query.ApplyTo(DBContext.Tasks_Objects.Where(i => i.Delete== null));

return Ok(items);
}

configuration of my controller/action in EDMModel.

var tasks_object = builder.EntitySet<Tasks_Object>("Task").EntityType.HasKey(e => e.ZAD_ID);

var task = builder.EntityType<Task>().HasKey(a=>a.ZAD_ID);

Answer 1

The problem is solved. "Extend" not working with LinqConnect because LQ using property EntitySet<> as a relation to other table, but we can change it.

There isn't problem with EF Core because EF Core using properties as a List<> not EntityRef.