Yes, I forgot to mention all that.
Moodle 4.3.3+ (Build: 20240405)
Mariadb 10.11.4
php 8.1.20
I also have the same problem on a version 4.4 platform (Build: 20240422). When I say the same problem, I'm talking about a course that won't save.
As a reminder, before emptying the mdl_backup_logs, mdl_backup_courses and mdl_backup_controllers tables, several courses were affected by this problem.
I have the impression that the backup task is deliberately jumping the gun, but I don't know what the trigger is.
As far as upgrades in a bitnami container are concerned, as long as there are no changes to be made to php and mariadb, this is done conventionally by replacing the files in the Moodle folder.
If the upgrade also requires the environment to be updated, I redeploy an updated container and import my database and moodledata.