NullPointerException on publishing page with non-published parent on top level

Steps to reproduce

1. Create space with versions and Comala Workflows activated (with workflow Scroll Versions Integration).

2. Convert the home page to a versioned page and leave it _In Progress_

3. Create a versioned child page under the home page

4. Route it to state Complete

5. Create a grandchild page

6. LEAVE this page in In Progress

7. Publish according version to a new space with option

   1. Publish only complete pages

8. Publish according version to existing space with options

   1. Publish only complete pages

   2. Also publish complete child pages

   3. Publish hierarchy

Actual behavior

NullPointerException

Expected behavior

The child page is published on the top-level