Using the exact same typeform, with the exact same URL passing a hidden field #ref. The link to the typeform used is the same every time. The link includes the hidden field populated with a code.
However, with hundreds of users signing up with this typeform, around 10% of the time that #ref is not recorded in the typeform results. It is blank.
Why would this be, everything is the same every time with this form, only in 10%+ of the results, the hidden field is not populated. Any ideas?