impossible to disable captcha for public users

in submission form template settings

I selected "no" to "display captcha for public"

in submission form now I don't see it, but still I get "empty value" error when clicking save button

if I also disable joomla recaptcha plugin then I get this error

Fatal error: Call to a member function checkAnswer() on a non-object in /home/agrietou/public_html/NEW/libraries/cms/form/rule/captcha.php on line 52

so I get that even when disabling captcha from submission form template, cobalt still look for it

maybe check this on your end