An Azure relational database service.
An old "earliest restore point" is a good sign. It means more restore history, not stalled backups. The SA password change had nothing to do with it.
To check, go to Backups then Retention policies and look at each database's PITR retention:
35 days: August 31 is expected. Azure keeps up to a week of extra backups past the retention period.
7 days: That's abnormal. Open a Microsoft support ticket, since Diagnose doesn't check backup health.
The database showing only 6 days likely has shorter retention, or was recently created, copied, or restored.