I've never had any issues with the BCC not working. I'd try forcing your cron to run through the command line – magento cron:run and see if that helps. Another thing you can try in your settings–Stores>Configuration>Sales>Sales Emails>General Settings>Asynchronous sending set to Disable. I was having issues with emails taking a long time to come through and my hosting company suggested turning this off and it helped immensely. Also double check you have the correct email in "send email copy to" section.
Good luck
