Resolved
Reported for: Toolset Forms 1.9.3
Resolved in: Toolset CRED 1.9.4
When you add required custom fields to a CRED form and JavaScript is disabled in the browser, the cred_form_validate
API hook will be run twice if the form is submitted and any of the required fields are not filled.
We are working on the solution to this problem.
Meanwhile, the only solution is to not disable the JavaScript in the browser.