We are getting an exception when a user clicks 'Start' on one of the Stages in their appraisal that states - 'Exception - Form already rendered'.

Stack trace: 

line 532 of /totara/question/lib.php: question_exception thrown 

line 205 of /totara/appraisal/appraisal_forms.php: call to question_base->set_preview() 

line 961 of /lib/formslib.php: call to appraisal_answer_form->definition_after_data() 

line 405 of /totara/appraisal/myappraisal.php: call to moodleform->display()

Has anyone had this issue before? Any ideas what might be causing it?  It seems like the $this->formsent  is being improperly set?