Groff renders round brackets and square root signs incorrectly

[kleinbottle4]

Hello,

Apologies if this has already been asked before.

The snippet main.ms (below) is fine if compiled with
        groff -e -ms
but renders incorrectly with
        groff -e -ms -Tpdf
if viewed with Atril, Evince or Firefox, but not with Chrome or gv.

This can be fixed by adding either
        -P-y -PU
or
        -P-e
to the groff options, but, in order to insert images, I need to
compile a PostScript file and then ps2pdf that.

>From reading around I think it might be caused by the PDF reader not
recognising the font, like in
<https://lists.gnu.org/archive/html/groff/2018-02/msg00012.html>

Does anyone know how to make it so that I can compile main.ps, and
then `ps2pdf main.ps > main.pdf` and get the equations rendered
properly?

Thanks,

kleinbottle4

P.S. attached are main.ps and main.pdf, which demonstrate the issue.

main.ms:

.LP
.EQ
sqrt left ( 1 over 2 right )
.EN

main.ps
Description: PostScript document

main.pdf
Description: Adobe PDF document