Hi Guys,
Came across this interesting incident when I was trying to figure out why contacts were created for every form submissions whilst I wanted the contacts to be created based on certain form field conditions.
Did some R&D and found out that when I added 'Add to Shared List' processing step for submits to be added to shared list, the contacts were being created automatically even after disabling the 'Update contacts with form data'.
Hope this saves you some time if ever you are in the same situation.