groff -Tpdf bug?

[Larry McVoy]

Hi,

I recently got a copy of John Gilmore's paper:

http://mcvoy.com/lm/papers/porting-berkeley.ms

and if I do

groff -ms -Tpdf porting-berkeley.ms > porting-broken.pdf

the pdf is not readable by firefox.  I get the popup that says 
"This PDF might not be displayed properly".

That file is there at http://mcvoy.com/lm/papers/porting-broken.pdf

If I do

groff -ms porting-berkeley.ms > PS
ps2pdf PS porting-berkeley.pdf

I get:

http://mcvoy.com/lm/papers/porting-berkeley.pdf

which displays fine.

This is on xubuntu (debian stretch/sid), groff version 1.22.3.,
firefox 76.0.1 (64 bit), x86_64.

Let me know if I can provide any more info.  

--lm