Any manual or scheduled action before that? I don’t think it can happen all on its own.
What are the BaseVersionName and ServerVersionName from About → System info?
If they’re not both 2.0.7.1 then find out where 2.0.7.1 update is, per layout given above.
How do you open GUI? Did you set TrayIcon --no-hosted-server? Do you type URL?
Many times people mess this up because Duplicati as service doesn’t mean there’s not
another non-service Duplicati around on another port that is confusing, as it’s different…