A fix for this should be in crew as 59acb9c7d90f. I have made extensive tests
with squid3, but please test whether it works for you, in particular if you're
using a different proxy server. 

Please note that crew has dropped support for 2.3, so people there would have to
make a custom version based off of 1.2.1 with 59acb9c7d90f transplanted (or
equivalent) - there are no current plans to create a 1.2.2 release, according to
mpm.