Idea plugin and composite builds

I am working on combining two code bases together and using the gradle composite build functionality to do this. This was working great in gradle 4.6, not only did the system build as expected but I was able to generate all the associated idea modules for all projects (including those in the composite build).

Something has changed and in 4.7+ releases and the idea plugin module generation no longer generates the *.iml module files for the composite gradle project, but the build of the class and jar artifacts still work as expected.

Is there something that must be added to the build script to get the idea plugin to generate the composite build project idea modules and hook them into the top level *.ipr file, or is this not supported anymore?