SKARA-768 implemented a check for issuetype, which must be one of: Bug, Enhancement, New Feature (which is not generally used), Task, or Sub-task. Specifically, it flags a bug ID with an issue type of "Backport", "JEP", "JEP Task", or "CSR" as invalid.
However, instead of blocking the PR from being integrated until the correct bug ID is used (which it should do), it merely notes it as a warning.