While https://issues.jenkins.io/browse/JENKINS-58979 prevent Support Core from generating offensive replacements, existing offensive replacements are not dealt with and remain. There are persisted in the com.cloudbees.jenkins.support.filter.ContentMappings.xml.

Support core should maybe automatically fix those or add an Administrative monitor about it and let the user hit a "Fix" button.

Note: there is also https://issues.jenkins.io/browse/JENKINS-55995 that can cause this. That Support Core does not refresh its mappings. Deleted items mapping remains.