So the question is whether the email is being generated and not received or if its not being generated at all. It is not unusual for certain emails in WP to be received and others to just disappear / silently rejected by the receiving server.
To answer this question, you would need to install an email logging solution of some kind. The one we use is MAILGUN which has great logs about what is happening to emails. But you can also use something like POST SMTP which would use your SMTP server to send emails and generate a rudimentary log.
Once that is installed and configured you can check the email logs to see if the emails are present in them. If they are present then within the logs you can see what happened to them. If they are not present in the logs then it means that the email is not being generated and you can start digging down to figure out why that is happening.