@nhoran The backup also failed after restarting the NTP services.
I just attempted to create a new empty database and created a backup. It succeeded in 2 seconds.
The size of the last succeeded backup was ~400 GB. The failure always happens after ~15 minutes. Data is written to GCS before failing.
Could the issue be related to the process running too long resulting in the GCS access token expiring? Even though the last succeeded backup completed in ~25 minutes.