Confusing error message

[AndreeaCristinaRadacina]

While working on a ticket, I noticed that the error message that appears by default is applied when min/max units are not respected.

The problem is that the default error message is "[field_name] is a required field", whereas the error, in this case, is that the user doesn't check enough checkboxes or checks too many.

I know we give the users the possibility of introducing their own error message, but I found this and considered it confusing.