The "Use a regular expression to include jobs into the view" option is not properly handled. Whenever a regex value is used, as soon as we save the page, it gets replaced by "on". I figured out the commit that introduced this bug: https://github.com/jenkinsci/jenkins/commit/8b9394dd69e3e7958058a517e303754f0193c982#core/src/main/java/hudson/model/ListView.java
I'll be working on fixing this issue