How to reproduce : 

• Create a form and set it a life cycle, and add it a field. 
• Add this form to a page through service "Form"
• On front, enter answers to the form and validate. 
• Repeat previous step so that form have at least 2 answers. 
• On back office, refresh the form and consult its data. 
• Select first line of data and update its state. 

=> Selection of first line is lost.