Sql-server – Backups jobs are successful but cannot see differential backup in the media

I have a backup job running on my Sql server that takes a complete backup at start of month and diff every two hour between 9 to 5.Now the problem backup jobs are running and successful but I cannot see differential backup in the media.

Backup job
USE [msdb]
GO

/****** Object:  Job [Backup]    Script Date: 04/06/2018 12:31:21 ******/
BEGIN TRANSACTION
DECLARE @ReturnCode INT
SELECT @ReturnCode = 0
/****** Object:  JobCategory [[Uncategorized (Local)]]]    Script Date: 04/06/2018 12:31:21 ******/
IF NOT EXISTS (SELECT name FROM msdb.dbo.syscategories WHERE name=N'[Uncategorized (Local)]' AND category_class=1)
BEGIN
EXEC @ReturnCode = msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'[Uncategorized (Local)]'
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback

END

DECLARE @jobId BINARY(16)
EXEC @ReturnCode =  msdb.dbo.sp_add_job @job_name=N'Backup', 
        @enabled=1, 
        @notify_level_eventlog=0, 
        @notify_level_email=2, 
        @notify_level_netsend=0, 
        @notify_level_page=0, 
        @delete_level=0, 
        @description=N'No description available.', 
        @category_name=N'[Uncategorized (Local)]', 
        @owner_login_name=N'Server\user', 
        @notify_email_operator_name=N'AdminOperator', @job_id = @jobId OUTPUT
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback
/****** Object:  Step [Step-1]    Script Date: 04/06/2018 12:31:21 ******/
EXEC @ReturnCode = msdb.dbo.sp_add_jobstep @job_id=@jobId, @step_name=N'Step-1', 
        @step_id=1, 
        @cmdexec_success_code=0, 
        @on_success_action=1, 
        @on_success_step_id=0, 
        @on_fail_action=2, 
        @on_fail_step_id=0, 
        @retry_attempts=0, 
        @retry_interval=0, 
        @os_run_priority=0, @subsystem=N'TSQL', 
        @command=N'DECLARE @File varchar(1000)
DECLARE @i int
declare @m as varchar(2)
declare @d as varchar(2)
declare @dt as varchar(8)
DECLARE @strSQL nvarchar(1000)
--if (day(getdate())<10)
--  set @d = ''0'' + cast(day(getdate()) as varchar(2)) 
--else
--  set @d =  cast(day(getdate()) as varchar(2)) 

if (month(getdate())<10)
    set @m = ''0'' + cast(month(getdate()) as varchar(2)) 
else
    set @m =  cast(month(getdate()) as varchar(2)) 
Set @dt = cast(year(getdate()) as varchar(4)) +  @m


SET @File = ''D:\SQLBackups\SQLBackups_database\database'' + @dt + ''.BAK''

EXEC master..xp_fileexist @File, @i out
 IF @i = 1 BEGIN     --FILE EXISTS
    set @strSQL = ''BACKUP DATABASE database  TO  DISK = N'''''' + @File + ''''''  WITH  DIFFERENTIAL''  
 END
 ELSE BEGIN --FILE NOT EXISTS
    set @strSQL = ''BACKUP DATABASE database  TO  DISK = N'''''' + @File + ''''''  WITH  INIT''  
 END


EXEC sp_executesql @strSQL


', 
        @database_name=N'database', 
        @flags=0
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback
EXEC @ReturnCode = msdb.dbo.sp_update_job @job_id = @jobId, @start_step_id = 1
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback
EXEC @ReturnCode = msdb.dbo.sp_add_jobschedule @job_id=@jobId, @name=N'Schedule-1', 
        @enabled=1, 
        @freq_type=8, 
        @freq_interval=62, 
        @freq_subday_type=8, 
        @freq_subday_interval=2, 
        @freq_relative_interval=0, 
        @freq_recurrence_factor=1, 
        @active_start_date=20100823, 
        @active_end_date=99991231, 
        @active_start_time=90000, 
        @active_end_time=190000, 
        @schedule_uid=N'50451ca4-7f63-45ce'
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback
EXEC @ReturnCode = msdb.dbo.sp_add_jobserver @job_id = @jobId, @server_name = N'(local)'
IF (@@ERROR <> 0 OR @ReturnCode <> 0) GOTO QuitWithRollback
COMMIT TRANSACTION
GOTO EndSave
QuitWithRollback:
    IF (@@TRANCOUNT > 0) ROLLBACK TRANSACTION
EndSave:

GO

Log: