The problem is the PDF logic on a localhost server cannot handle an absolute URL path to the icon image. It does work with a relative path.
I just update the files on github to change the logo path to a relative path on all export template. This is version 2020.3.20. If you have your own template, you can remove the holiday_logo function from it as the logo value passed to the template is correctly modified and any holiday logo resolved before it is passed to the template.
The holiday_logo function in the template still exists but does not change anything. It will generate an entry in the error_log file indicating that the template should be updated. This is done so that your template will process correctly even with this function still in it.