Squid is compiled with --with-pidfile=/var/run/squid.pid. Without PIDFile=/var/run/squid.pid in the service file systemd always guesses wrong the main pid.
squid-3.2.3-2.fc18 has been submitted as an update for Fedora 18. https://admin.fedoraproject.org/updates/squid-3.2.3-2.fc18
Package squid-3.2.3-2.fc18: * should fix your issue, * was pushed to the Fedora 18 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing squid-3.2.3-2.fc18' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2012-16962/squid-3.2.3-2.fc18 then log in and leave karma (feedback).
squid-3.2.3-2.fc17 has been submitted as an update for Fedora 17. https://admin.fedoraproject.org/updates/squid-3.2.3-2.fc17
squid-3.2.3-2.fc16 has been submitted as an update for Fedora 16. https://admin.fedoraproject.org/updates/squid-3.2.3-2.fc16
squid-3.2.3-2.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.
squid-3.2.3-2.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.