"Last Backup Date" is being reset in SQL

I have an issue with my Enterprise Vault Database backup. I ran a database backup on Friday, and when I checked afterward, the database properties told me the correct date for "Last Database Backup". When I check back today, I see that both my Directory database, vault store database and fingerprint database are set to "none" when I check "Last database backup".

How could this happen?
The Agent for Enterprise Vault for Netbackup is being used