The calculated amount that is passed to Stripe is being cleared upon submission

In my form, I have a required 'session choice' field to select 1-4 sessions, each $20. That total is calculated (pre-cost field).

When you select 4 sessions, another  hidden field appears($5 discount), for you to check and receive the discount. 

The total is then recalculated  with the second visible 'Total Cost' calculation field and the value in the total cost calculation field is passed to Stripe.

Those amounts all appears to be calculated and passed to the display in stripe payment.

However, when I click 'submit', the calculated amount disappears during the submission and I get an error page that says the required 'session choice' field is blank. When I return to the form, all fields have the data entered except the choose your session field and calculation fields. They have disappeared.

It seems when I click submit, Stripe is erasing the calculation and the choice of sessions.

This is in test mode currently, which usually works for me in situations like this.

Make sure to do not clear hidden field values when submitting the form. Go to Preferences > Advanced tab > Click "Show More" button > Set "Clear Hidden Field Values" to "Don't Clear":