This thread is resolved. Here is a description of the problem and solution.
Problem:
The issue here is that the user was using some custom JS to submit their form but it was targetting the wrong form.
Solution:
This was happening because they were using the generic classname for the submit button. They also had multiple forms on the page which uses the same classname.
In order to target a specific form you will need to change the form submit button class name or to target the form itself by its specific ID.
In this case we added an extra class name to the submit button.
I took a look at the code Minesh had provided and the problem with having the multiple forms on the page is that your code isn't targeting a specific form.
I would suggest giving your form's submit button a unique name and update the JS to target that specific submit button.