Commenting by email with an attachment does not send notification for Reporter and Request Participant

Issue Summary

Reporter and Request Participant cannot receive notification when comment is added with an attachment from an incoming email. Our documentation here says:

When JIRA applications process mail to add comments, if an attachment is included in the email it will fire an Issue Updated event instead of an Issue Commented event.

However, as per JSDSERVER-4506,

there're certain events where Customers (Reporters, Request Participants) do not receive notifications e.g. Issue Assigned, Issue Moved, Issue Updated.

This caused the issue where Reporter and Request Participant cannot receive a notification when a comment is added with a screenshot, as it fires an Issue Updated event but that doesn't work for Customer Notifications apparently.

Environment

Jira 7.13.x
Jira 8.2.x

Steps to Reproduce

1. Have a comment added to a ticket with a screenshot attached on it, using an incoming mail (not from the UI)
2. Have the Public Comment Added rule configured for Customer Notifications

Expected Results

Reporter and Request Participant should receive the notification

Actual Results

Reporter and Request Participant won't receive any notification.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available