Zoom Event Registrations Report API Issue

We have a couple of people who registered for an event on scheduled event day . for these registrations details are not coming from event registration reports api. we are using registration report api to find out attendance so this is caused issue in attendance integration. can you please help us to understand is this expected behavior of api ?

No it’s not expected behavior. How did they register? Are you using a third party app and then trying to verify via api? @events3