I have noticed the same, the stable didn't had this problem.
Havp is working, well I see the process slurping CPU when I download a big file.
Looks like squid isn't caching. I will install the stable on a testmachine and look and the squid.conf/.tmpl if there are any differences.
Endian is great firewall/router but some support from the dev guyz would be appreciated
rgdz,
Bhai