After upgrading to 17.3 RU12 the hidden fields are validated as required.
-> Until 17.3 RU5 specifically before the fix T6D9638 the hidden fields which were required are not validated.
-> Since ugrading to 17.3 RU12 the fields which are not visible in the form are validated and unable to save the request.
-> When trying to save below error is seen though fields are not visible:
Release : 17.3
Component : Catalog - Customizations
This is resolved by SE via defect DE64915 and fix is included in 17.3 RU15.