Consistent VSS shapshot errors for SQL 2012 server during nightly jobs only. Daily backups are working. (4044716)

During nightly backups, an error is generated: "VSS Full snapshot of <disks_list> on <agent_name> failed due to writer 'SqlServerWriter' VSS error: WriterErrorNonRetryable. The SQL log truncation for the protected machine <agent_name> on volumes <disks_list> has failed."

Daily backups using same VSS are working normally.

To resolve the issue please download and install Microsoft SQL Server 2012 SP4 https://www.microsoft.com/en-us/download/details.aspx?id=56040

Server should be rebooted after SP4 installation. To verify that issue has been resolved, please do the following:
- open Core console
- click on SQL server agent name
- on the right pane, click on SQL drop-down and select Force Log Truncation

Full VSS backup with log truncation will be initiated.