I have a form which is regularly missing user input data in the submission.  The data seems to always be missing from the same part(s) of the form, but they are not the same type, nor are they in the same section.

I have highlighted the portion of the form which seems to fail most frequently (I cannot say 100% that other info is missing sometimes because staff are most impacted when these are not done.  There is a radio button with a default value, one set is from a collection (all required), and another is in a table (all required).

When I go into monitor, none of the variables are present.  The highlighted variable with no value is a radio button that has a set default value so there is no way the customer should be able to remove any value as the radio button is already active.  

Any thoughts on where to look for the problem and why it is happening intermittently?  I do NOT want to have to remove this service for our customers, but it is frustrating staff and customers when we are having to repeatedly ask for information they have already provided.  It is causing us to look bad.