java.lang.IncompatibleClassChangeError: Found interface com.android.tools.idea.gradle.project.model.GradleAndroidModel, but class was expected

I release a plugin for Android Studio 251 and suddenly started to see a lot of these errors happening. Checking at the source code of 243 and 251, the GradleAndroidModel seems to remain a class in both versions … why is it complaining about expecting an interface now? Has anyone experienced this before?