Update complain.conf

grep -s should be set i think:

       -s, --no-messages
              Suppress error messages about nonexistent or unreadable files.  Portability note:  unlike  GNU  grep,  7th
              Edition Unix grep did not conform to POSIX, because it lacked -q and its -s option behaved like GNU grep's
              -q option.  USG-style grep also lacked -q but its -s option behaved like GNU grep.  Portable shell scripts
              should  avoid  both  -q and -s and should redirect standard and error output to /dev/null instead.  (-s is
              specified by POSIX.)