Several users have reported and encountered problems with Libreoffice printing.
The problem is Libreoffice printing blank pages when attempting to print to printer and/or export to pdf file.
This occurs in releases 20.04.0, 20.04.1 LTS and the 20.10 BETA
The solution is to go to Preferences-LXQt settings-Session settings - Environment variables - Environment (advanced) -
then add the following 2 variables if they are missing -