I searched for my problem on the CB forums but couldn't find a solution for this strange behavior.
On one of my sites I installed the upgrade from April 28th this morning. From that moment on, the cb login redirect no longer works. Whatever I do, after login, the user always visits the site/ ͕͍ ͕͍ձմ͡ɐ (yep, Chinese characters) instead of site/dashboard.
Just before upgrading to the latest CB, i updated joomla and the gantry framework.
I've partially addressed this problem. I've integrated Moodle within Joomla via Joomdle. It looks like it's going wrong with the login process in Moodle (Joomdle plugin). I've no idea what's going on yet but that's not an issue to discuss on this forum.