I found a problem on WEBCON with regular expression. In the attributes, in the "Style and behavior" tab, in the Regular expression for validation field. In my case, I set a limit to 11 digits (11 characters long, as in the Polish PESEL number) - "\ d {11}" to be precise. This regular expression works and detects the shorter string as bad. She recognizes even 11 digits as correct, that's good. More characters (e.g. 12 and not recognized as an error and allows you to proceed further on the form.
Does this also happen with you?
Is this invalid regular expression in WEBCON?