@Pilow The backups kept by LTR are just regular backups with a specific tag, which doesn't change how we treat them.
If you want to avoid each of your LTR backup to depend on one another, we recommend to set a full backup interval value to your backup job, which will regularly force a full backup. (even without LTR, having an infinite chain of backups can cause problem in the long term, especially if no healthchecks are made)