Ian,
I've done a bit of looking today, and hopefully have an answer for you. We'd love it if you could make the following modification to our SCLogin module, and if it works, let us know. We'll include the change in the upcoming 4.1.1 release.
Edit the /modules/mod_sclogin/helper.php file. Around line 124, you'll see the following (in the getLoginRedirect function):
if ($router->getMode() == JROUTER_MODE_SEF)
Simply change that to:
I'm honestly not sure why we're doing the code like that. It was likely copied originally from the Joomla login module, but don't really think it's the right way to do what needs to be done.
Anyways, please test, and let us know how it goes. Hopefully, this will fix you right up.
Thanks, and good luck,
Alex