Currently, you redefine agent on a new method, but $self->_agent will still passthru to the LWP::UA version. Since _agent is actually a documented method (ie: non-private), you should redefine _agent to be the same thing as the new method default.
sub _agent { "WWW::Mechanize/$VERSION" }
sineswi...@gmail.com reported on Jul 20, 2012
Details
Imported from Google Code issue 238 via archive