I have two Paypal forms on a pre-prod website.
The first is working fine and redirect to Paypal ,you can test it here:
The second (a duplicate of the first but text is in english) doesn't redirect to Paypal:
In this form, the total field doesn't work (and I don't know why) and I disabled the Paypal condition (but result is the same, no redirection).
The forms have obviously their own Paypal feed, and they use the same informations (a Paypal sandbox account).