Data Retention and Storage Policy

Check the Data Retention Forecast and Compliance Report, it will advise why a particular job is retained pass its configured retention

https://documentation.commvault.com/2024e/expert/data_retention_forecast_and_compliance_report_overview.html

The report initially indicates:

then subsequently

However, it is still unclear to me why the data does not expire. Are the cycles of the policy set to 0 incorrect? Is it not possible to manage a data expiration after 1 year with an initial full backup and subsequent incrementals ?

Thanks

The data is not aging because recoverability rules still apply when using 0 Cycles. 

In simple terms, your current Incremental backup is dependent on the preceding Full + Incremental backups for recovery, so the preceding jobs will not be aged until all jobs in the Cycle have met their retention requirement.

You may need to consider performing periodic Full / Synthetic Full backups to close off Cycles.