Hello Damodar. As mentioned in your other thread, if you are testing this with an Access Profile, this appears to be the same current issue.
Patrick Gookin confirmed that form data is currently not available in the provisioning plan for Roles and Access Profiles, and SailPoint is working on a fix. (Patrick’s update)
Because of that, your Before Provisioning rule will not have the form data available to pass as AccessRequestFormData.
For comparison, @trettkowski reported that, after testing with Professional Services, the Before Provisioning injection approach worked for his direct Entitlement requests. He was not able to get the same approach working for Roles or Access Profiles.
I would suggest testing the same form with a direct Entitlement request. If that works, it would strongly indicate that you are hitting the known Access Profile issue.