Squidgaurd and Squid 2.0, only blocking sites for some computers

[rustid]

We have facebook blocked at our office using squidgaurd and squid 2 on pfsense 2.0 release.  Some users are still getting access to facebook and some are getting redirected back to google like they should be.  All have IP addresses in the range set in the Group ACL.  Haven't noticed youtube so much getting through, but I am seeing youtube on the lightsquid report.  Any ideas as to why this is happening?

[Nachtfalke]

Facebook can be reached via httpS and this will not be filtered by a transparent running squid proxy ans so squidguard cannot detect this traffic.