Custom field regex - valid class

-- HikaShop version -- : 4.7.2
-- Joomla version -- : 4.3.1
-- PHP version -- : 7.4.33
-- Browser(s) name and version -- : Chrome latest

Hello,

I created a custom field regex and custom error message - for a telephone field.
Regex works, custom error message appears, but the field has still a "valid" class, so it's not clear for user which field is invalid. Why is that so? I attach a screenshot.

Thanks for your help

Thank you.