Symptoms
You may see that an account's backups do not contain the databases used by the account, despite no errors appearing in the backup log.
Description
This can happen if the databases are not mapped to the account. The account backups will only contain databases that are mapped to the account.
Workaround
Databases can be mapped to the account in the following location of WHM.
Home > SQL Services > Database Map Tool
Databases created within cPanel are automatically mapped to the account.