Hi,
I found out that in its standard distribution the odoo module in ns8 is unable to produce PDF reports correctly.
The logs says wkhtmltopdf: Exit with code 1 due to network error: TimeoutError
To solve this you need to activate the developper mode and in Settings > Technical > System, you need to add those two key - values pairs :
report.url.freeze True
report.url http://localhost:8069
Source : https://www.odoo.com/fr_FR/forum/aide-1/odoo-pdf-report-format-issue-solved-189421
@Gian8 that should probably be corrected in future releases.