YANG "if-feature" statement

YANG
6

We have an issue after upgrading the confd version to 6.3.0.2, In the previous version if-feature works fine without any issue. In the below code “mandatory true;” not worked.
Looks like it is enabled by default. How do we enable specific

    tailf:action turboramtest {
           tailf:actionpoint fosdiagtests;
         input {
            leaf slot {
                if-feature platform_chassis;
                type slotidtype;
                mandatory true;
            }