There are some Jenkins jobs with the Active Choices Reactive Parameter list. This list if dynamic list and the values are from the Database table and its is working fine most of the times.
Sometimes, this list is showing empty. If Configure button is clicked followed by apply -> save without changes , its working fine.
The operations apply -> save changes the contents of the config.xml file. The main differences are , the before changes config.xml have <classpath/> and no <projectName> element.
Attached is for your reference.