Example:

package a;
public interface Foo {
    FooImpl.I getI();
}

package a;
public class FooImpl implements Foo {
    public interface I {
    }

    public I getI() {
        return null;
    }
}

Result after pulling up "I" or moving "I" into Foo:

package a;
public interface Foo {
    FooImpl.I getI();      // <<< should be just "I" now

    interface I {
    }
}

It's a rather exotic case, but can happen after "Extract Interface" and forgetting to select the inner interface, and correcting this by pulling up the interface in an extra step.