I saw this at one point (I believe when I was on v14 manual install). I am on a docker install now with v13 and don’t see this issue. When I had the problem, this worked as a workaround- Print Get PDF issue in new installed server - #7 by Solufy
FWIW, v13 docker uses:
frappe@b35dbec1f686:~/frappe-bench/sites$ wkhtmltopdf -V
wkhtmltopdf 0.12.6 (with patched qt)