Why do my security changes for exported pdf file not work?

When exporting Writer file to pdf, I changed the Security settings to NOT allow printing, changes, or copying, but the resulting PDF file DOES allow printing, changes and copying when opening in Okular. LO version: 7.0.0.3 Ubuntu Linux. Thanks.

Hello,

as stated in my comment to answer in question PDF security options this is bug #tdf127914 and obviously it has been reported by yourself:

image description