AWS Backup for rds failed an hourly job and missed an hourly job

I have created a backup plan to backup a DB instance (MariaDB). The backup rule was set to run the backup hourly with 2 day retention starting at 11:00 UTC The list on the backup vault is: 9/12 creation time (UTC) 11:00, 12:00, 13:00, 14:00, 15:00, 16:00, 17:00, 18:00, 19:00, 20:00, 21:00, 22:00, (missing) 10/12 creation time (UTC) 11:00, 12:00, 13:00, 14:00, 15:00, 16:00, 17:00, 18:00, 19:00, 20:00, 21:00, (failed), 23:00

The Backup jobs listing is consistent with the backup vault listing. The list on jobs for 8/12 is also showing missing of 23:00 job 8/12 creation time (UTC) 11:00, 12:00, 13:00, 14:00, 15:00, 16:00, 17:00, 18:00, 19:00, 20:00, 21:00, 22:00, (missing) Jobs (AWS Backup->jobs) can be viewed 7 days, so the listing for 8/12 is not in Backup Vault but Jobs.

1. I can see one job failed at 23:00 UTC on the job listing (AWS Backup->jobs).

The error description is:

Invalid lifecycle: 
Backup job xxxxD-xxxx-xxxx-xxxx-xxxxxxxxxxxx could not start because it is either inside or too close to the weekly maintenance window configured in RDS instance.

When I checked the DB instance (RDS->Databases->modify) the backup configuration for retention is set to 0. I also checked the listed for Automated Backup (RDS->Automated Backup), the DB instance is not on the list. i checked the DB instance configuration, the 'Enable auto minor version upgrade' is set to Sunday 12:08 UTC

2. Why is the job missing at at 9/12, 23:00 UTC? And no error for that missing job was shown on the job listing?

3. Missing backup between 00:00 to 10:00 UTC. Should I change the start time to 0:00 UTC so that the backup will also bakcup between 00:00 to 10:00 UTC?

4. What is the difference between creation and start by time on the backup job listing (AWS Backup->jobs)?