Hello [Azure User]
You are correct, the windows file and folder backup agent from azure backup service is often referred to as "MARS" its abbreviation is "Microsoft Azure Recovery Services" used in many other features by Azure Recovery Services.
Coming to your issue, to confirm if your backup is consistent you can do a iSCSI mount of the volumes and browse through the recovery point to ensure the integrity of the backup. This link here got detailed guidance on how you can do that
https://learn.microsoft.com/en-us/azure/backup/backup-azure-restore-windows-server
Now, for the actual issue..
It appears to be an issue with the overview blade. You need to report this to azure technical support team to do the required diagnosis, they will have to fix this from the azure service side for you. You need to provide them with the network trace capture of the browse as you reproduce the issue. This article might help you collect those traces
https://learn.microsoft.com/en-us/azure/azure-portal/capture-browser-trace
As long as you backup is intact you need not worry. This may be cosmetic issue and can be fixed.
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