The backup is run by a 'Database Maintenance Plan' (which I did not setup) with a vanilla set of parameters for a daily backup.

However, a clue to the oddity may be in the following BackupMediaFamily record for the backup:

media_set_id: 14133

family_sequence_number:1

media_family_id:B3A6F86C-0000-0000-0000-000000000000

media_count: 1

logical_device_name: NULL

physical_device_name: 80F398C7-58AC-4DC6-BC15-0B2BE1A62C8E}8

device_type: 7

physical_block_size: 1024

I do not know what device_type: 7 is?

thanks