I think there are a couple of misunderstandings here.
@Tut is just a forum moderator here; though he has a lot of experience with the software and a saint’s patience in providing assistance for it, he doesn’t have any contact with or input into the development of the software itself. @lubos is the software developer.
The problem with the
To confuse things even more, the desktop version of Manager for Windows will always use the Windows rendering engine, which is Internet Explorer for older versions of Windows and (presumably) Edge for Windows 10 - irrespective of what your preferred/default web browser is set to (I’ve tried installing Manager Desktop on a machine without Internet Explorer in the past, and it failed to run).
A diagnostic approach would entail creating an identical HTML page and loading it into IE/Edge (depending on your operating system), then seeing how it renders and prints from there. Unfortunately, I have no idea of how one could extract the HTML generated by Manager to perform this test.