Custom validation not working

In my registration form I use this customer validation code to verify the format of the information provided by the users.

One of the field is now accepting any input while the custom validation should check against this format
/^[A-Z]{6}[0-9]{2}[A-Z]{1}[0-9]{2}[A-Z]{1}[0-9]{3}[A-Z]{1}|[0-9]{11}$/

But another field custom validation is working fine
/^[+]{1}[3]{1}[9]{1}-[3]{1}[0-9]{2}-[0-9]{6,7}|[+]{1}[4]{1}[1]{1}-[7]{1}[6-9]{1}-[0-9]{7}|[+]{1}[4]{1}[2]{1}[1]{1}-[0-9]{3}-[0-9]{7}$/

The only difference I can see between these two fields is the the first one depends on another field.

If I modify the field definition removing the dependency the validation works.

Yes, the client-side validation will not work on dependent fields. It should validate server side though.