Machines aren't getting tagged with its respective zone in RHOCP 4.13

IHAC who has configured regions and zones below:
~~~
 1. Region : DC1
 2. Datacenter: NDC
 3. Three Availability zones & failureDomains (same name): ZA, ZB & ZC 
~~~ 
As per CU non-default worker machinesets for each zone but machines aren't getting tagged with its respective zone (only region tag is working)  

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    Avability zone is empty in openshift-machine-api project.

     Avability zone should contain the respective zone name in openshift-machine-api project.

    Case id: 03781401
    Attached screenshot in the case would help much.
    Must-gather avaliable