10.7.4 has a spring loose

Whilst imaging the Mac minis, I’ve discovered a rather annoying bug in Lion’s 10.7.4 update that makes the URL icons in the dock disappear.  Instead of being a natty ‘@’ spring, they now just appear as a blank space.  We make use of the fact you can put URLs into the dock via Workgroup Manager to allow children to automatically log into Purple Mash, and so this is rather annoying.  It’s also annoying because I’ve imaged several Macs already and don’t want to have to go and fix them.  Some people have suggested a fix for the problem, but I’ll probably just wait until an official fix comes through Software Update.