If the jira.projectkey.pattern is set to "(([A-Z0-9]{0,5}-)?([0-9]{4})){1}", when adding the "issue key" in the the comment, it will return an output "project key""issue key".

For example, if my project key is TEST-1234 and the issue key is TEST-1234-01. So, once the issue key is added in the comment it show up the text message "TEST-1234TEST-1234-01" as in the screen shot.