Warning: array_filter() expects parameter 1 to be array message

Hello, I've created a form and then I copied it to use it with another language.
I've changed the labels of each field and the rest is like the original.
When I use the new form the information is sent correctly but after sending the data the program shows the next error/warnign lines:
Warning: array_filter() expects parameter 1 to be array, null given in
/usr/home/mysite.com/web/libraries/cegcore2/libs/arr.php on line 70
Warning: Invalid argument supplied for foreach() in
/usr/home/mysite.com/web/libraries/cegcore2/libs/arr.php on line 72

If the user uses the first/original form the warning lines are not displayed. Thank you.
PD: I'm using Joomla 3.1.15, php v7.2 and the lastest chronoforms v6

Hard to find the issue without testing the form itself!