kern.proc.pathname errors for an old Linux executable

[UnitedMarsupials]

Some times I indulge in playing an old game of Civilization -- a 32-bit Linux binary named "civctp". Its multiple threads each appear as a separate process, and lsop flags each of these processes thus:

lsop: sysctl: kern.proc.pathname: 35747: No such file or directory
   pid    jid stat command
 35747      0 miss (civctp)
lsop: sysctl: kern.proc.pathname: 35748: No such file or directory
 35748      0 miss (civctp)
lsop: sysctl: kern.proc.pathname: 35750: No such file or directory
 35750      0 miss (civctp)
lsop: sysctl: kern.proc.pathname: 35751: No such file or directory
 35751      0 miss (civctp)
lsop: sysctl: kern.proc.pathname: 35752: No such file or directory
 35752      0 miss (civctp)
lsop: sysctl: kern.proc.pathname: 92658: No such file or directory
 92658      0 miss (civctp)

I am not sure, what should be done, when the sysctl fails -- perhaps, something can be borrowed from the lsof-code?