When changing to a language whith a comma like decimal separator (example: English to Spanish), I get an error messing when the form validatesthe following fields:
'submission grade to pass'
'assestment grade to pass'

I've traced back the source code and I've detected that the issue comes from the script formslib.php which generates validation functions with incorrect regular expressions, when the language is set up with the comma as decimal separator (which is the case of the Spanish language, in opposite to English which uses '.'):

var regex = /(^{?\d\d*\.\d*$)|(}?\d\d*$)|(^-?*.\d\d$) /;

According to the Spanish setup, the correct expression should be

var regex = /(^{?\d\d**,\d$)|(}?\d\d*$)|(^-?*,\d\d$)/; (whith comma , not point)