The main issue and reproducible examples are described in https://youtrack.jetbrains.com/issue/IDEA-272024

The problem is in file https://github.com/jenkinsci/jenkins/blob/master/core/src/main/resources/dsld/IntelliJ.gdsl 
It doesn't compute type of properties my and instance properly, making them have just an empty type. There is a problem with IDEA because we do not expect that properties may have empty type, and we will fix it. Nevertheless, I doubt that you want to generate such properties and I believe it is a bug in your GDSL file.