Mixing include and extends does not work

[klr8]

Imagine the following template setup:
main.jinja.yml:

{% include 'part1.jinja.yml' %}
{% extends "shared.jinja.yml" %}

shared.jinja.yml:

---
{% include 'part2.jinja.yml' %}

part1.jinja.yml:

part: PART1

part2.jinja.yml:

part: PART2

Evaluating main.jinja.yml will result in an output file that looks like this:

---
part: PART2

Notice that PART1, which is included by the main template, is missing.

Jinjava version 2.7.1.