This solution was provided by Joy Melendez. It has earned a $100 donation to FIRST.
Troubleshooting challenge:
A JMWE validator is being used during the issue creation step. It validates that the issue has a certain linktype associated with it. The validator works properly when issues are being created. However, it doesn't work when a user clones an issue in Jira UI - even if the 'clone links' option is selected.