Until recently, users could submit questionnaires although empty.
To avoid this, last week you the warning message “Some responses are missing. Please complete all questions before submitting” was introduced at the end of the questionnaire.
Now, specific questions of the questionnaires are checked (so that users do not have to go back but are immediately prompted with a message). Unfortunately it does not work with sliders questionnaires when they include “0” as an option. For instance, users are not able to score 0 at the PHQ-9 / GAD-7.