Why some fields are missing on my PDF report of submission?

Hi 

I added a middle name option to my form but it does not show up on my PDF submission even though I edited the submission.  

I have checked your form and report, I can see what you're referring to; however, upon checking the PDF customization page for your form I can see that the fields is not currently included: 

What I would suggest you is to go to the customization page and click on the reset button so all the fields in your form are included in the report:

Hope this helps.