Hi Marlon,
We are in the middle of the final testing. We are aiming to do the release next week, and it would include the fix to multi-choice questions.
Moodle isn't designed to downgrade. My suggestion would be to return to 3.10. There is a forum dedicated to "Installing and upgrading help". Please remember to make a backup of your moodledata and database before any upgrade.
Kind regards,
Isabel