The first time we send an email thread to an existing JIRA issue, we want the whole thread. Thereafter we want only the latest message in the thread.
On the theory that JIRA distinguishes one thread from another by the subject line, I set the incoming mail handler to strip quotes, and then expected to get the whole thread the first time I added the JIRA ID to the subject line. That theory is clearly wrong. Every time, whether the thread is new to the JIRA issue or not, what I actually get is: sometimes the whole thread; sometimes only the latest message; sometimes something in between! (Moreover, the subject of the thread is apparently lost when the material is pulled into JIRA.)
I'm hoping there is a way to edit the thread before sending it the first time, but for that to help, we need to know how JIRA determines where the quoted material in a string begins.
Better still, of course, would be for JIRA to check the subject of the thread, and stripping quotes (in a consistent manner) only if the issue has previously received comments with the same subject. But until then, we need a workaround.
Notes:
A) We are on JIRA Cloud.
The question here is about adding comments to an existing issue.The option to create a new issue from email is not germane.