Trying to get property 'parentNode' of non-object when using scheduler for system report

[mzhaase]

Describe the bug

We have a system report without a template.

We can manually download the report via the UI.

Running icingacli reporting schedule run results in this error:

ERROR: ErrorException in /usr/share/icingaweb2/modules/reporting/library/Reporting/Reports/SystemReport.php:27 with message: Trying to get property 'parentNode' of non-object

Other report types work fine with schedules.

To Reproduce

Steps to reproduce the behavior:

1. new report
2. timeframe: 4 hours
3. template: empty
4. report: system
5. create schedule for report
6. frequency: minutely
7. action: send mail
8. type: pdf
9. icingacli schedule run
10. wait

Expected behavior

Error should not happen

Screenshots

Your Environment

• Module version: 0.10.0
• Dependent module versions:
• Icinga Web 2: 2.10.1
• pdfexport: 0.10.1
• Web browser and version: chrome 102.0.5005.63
• Icinga 2 version used (icinga2 --version): r2.13.3-1
• PHP version used (php --version): 7.3.31-1~deb10u1
• Server operating system and version: Debian 10

Additional context

Add any other context about the problem here.