An accidential trailing space in a user's email address will cause CreateOrCommentHandler to fail.

The error message is:
"The mail 'FROM' does not match a valid user
This user is not in jira so can not add a comment: "censored" <censored@censored.edu>"

So "example@host.com" doesn't equal "example@host.com " which is technically true but maybe a trim() would weed out this error since it can be easily overlooked.

However, sending email to the user with the space works.