Eclipse task doesn't work with includeFlat for multiproject

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1

I’m using Gradle 2.4 and trying to build up a multiproject with the following configuration.

project structure:

root
\project-a

root build.gradle:

subprojects {
    apply plugin: 'java'
    apply plugin: 'eclipse'
    sourceCompatibility = 1.8
    targetCompatibility = 1.8
    
    eclipse {
        classpath {
            downloadSources=true
            downloadJavadoc=true
        }
    }
}

root settings.gradle
includeFlat 'project-a'

gradle project-a:tasks doesn’t show the eclipse task.

When I change includeFlat to include the eclipse task becomes available for project-a. Can someone explain why?