So much missing information.
Have you added any other scripts or actions to reset the form?
What program are you using to fill-in the form?
Can you provide a link to the form or a sample form that exhibits the same symptoms.?
I didn't add any other script or actions to reset the form.
I'm filling the form with Acrobat Pro
It would be best to be able see your form if you can share it or a sample form that exhibits the same problem.