"Job failed because another backup job was in progress"

I'm using Azure Backup on my Windows 10 Surface Book. My backups are configured to run twice daily: at 7am and 7pm. Almost always, when my backup starts, 2 jobs will start at the same time. One will complete successfully and the other will immediately fail with the error "Job failed because another backup job was in progress".

Any ideas why 2 jobs are trying start at the same time?