Hi,
as usual our first question: Which version of LS are you using?
My only way to reproduce this in 3.29.17. was:
Close the browser before this question or in this question without clicking anything.
and
Export the data with option "full answers"
But I could not reproduce a case that one respondent has all three states in his response.
Either ALL subquestions have the text "N/A" or NONE
With option "Answer codes" everything is fine.
Usually you always export the codes (preferable with the conversion of "Y" and "" to a numeric code.)
So, please, explain step by step how we can reproduce your issue.
Joffm