User not redirected to Virtuemart cart after registration

When a user puts a product in their shopping cart and then registers a Virtuemart account as part of the checkout process, they aren't redirected back to their shopping cart - the registration goes through, but they're just redirected to the same VM registration page. This problem doesn't happen when I turn Joomdle off (Joomdle 0.9, Joomla 2.5, VM 3, Moodle 1.9).

Joomdle R0.9 has never been tested with VM3, so it may even not work at all (I can't remember the changes now)

That said, you can try enabling redirect-less SSO in Joomdle in Joomla, to see if that helps (assuming joomla and moodle are on the same domain)