Dynamic methods of a domain class from an inline plugin are not available in other plugin for integration testing or run-app

I have the following scenario:

my-app-domain (plugin)
my-app-other (another plugin that uses my-app-domain as inline plugin)
my-app-main (main app that uses my-app-domain and my-app-other as inline plugins)

When running test-app or run-app in my-app-other, the dynamic methods of a domain class from my-app-domain are not available.
In the main app this problem does not occur. I'm migrating a larger app from Grails 1.3.6 where this works like a charm.