Hi @eds,
You may sometimes end-up with these sort of issues if you do not restrict your questions as mandatory ones. Kindly please note that if a question is not mandatory the enumerators can skip and save the survey form as completed (which can eventually be submitted to the server). Try making your survey questions mandatory as outlined in the discussion below and you will not be receiving empty submissions (where an empty case is not allowed to be submit to the server).
Have a great day!
