Backups encrypted without choosing the "encrypt local backup"

I plugged my phone in and did a backup using the itunes app provided by microsoft on my laptop.

After the backup was done, I checked for the file and saw that it was encrypted even though I DID NOT click the checkbox to encrypt the backup.

I now cannot access this backup because it is encrypted by an unknown password. Tried the phone's lock screen as well as ALL current and previous Itunes passwords and still cannot access the backup.