SQLite error: no such column, but I don't have even such property or anything with that name

using System;
using System.Collections.Generic;
 
namespace ReminderApp
{
    public partial class CompletedTask
    {
        public DateTime CompletionDateTime { get; set; }
        public int TaskId { get; set; }
 
        public virtual CurrentTask Task { get; set; }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
 
namespace ReminderApp
{
    public partial class CurrentTask
    {
        public int Id { get; set; }
 
        [StringLength(100)]
        public string Task { get; set; }
        public DateTime Date_Time { get; set; }
 
        public virtual ICollection<CompletedTask> CompletedTasks { get; set; }
    }
}

using System.Data.SQLite;
using Microsoft.EntityFrameworkCore;
 
namespace ReminderApp
{
    public partial class TasksContext : DbContext
    {
        public TasksContext() : base()
        {
        }
 
        public TasksContext(DbContextOptions<TasksContext> options)
            : base(options)
        {
        }
 
        public DbSet<CompletedTask> CompletedTasks { get; set; }
        public DbSet<CurrentTask> CurrentTasks { get; set; }
 
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder.UseSqlite(@"DataSource=Tasks.sqlite;");
            }
        }
 
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<CurrentTask>().HasKey(item => item.Id);
            modelBuilder.Entity<CompletedTask>().HasKey(item => item.TaskId);
        }
    }
}

        public static string[,] GetCompletedTasks()
        {
            TasksContext Context = new TasksContext();
            CompletedTask[] TasksArray = Context.CompletedTasks.ToArray(); ([U][B]the error is thrown here[/B][/U])
 
            string[,] Results = new string[TasksArray.Length, 2];
            for (int i = 0; i < Results.GetLength(0); ++i)
            {
                Results[i, 0] = TasksArray[i].TaskId.ToString();
                Results[i, 1] = TasksArray[i].CompletionDateTime.ToString();
            }
            return Results;
        }