Gradle Task triggers Eclipse incremental build

We habe a C project that also has Gradle nature, cause we use Gradle to wrap the actual compilation and also for a bunch of support tasks.

Now everytime we run a Gradle Task from the Gradle Tasks view, the whole Eclipse project build is triggered, even for simple help tasks like “projects”.
Is this by intention? How can we make it stop?

I filed https://github.com/eclipse/buildship/issues/1046