API 2 Filter on actionunixtime not working

How is this supposed to work? I have a query that I'm passing to the API like this: https://mydomain.com:2083/json-api/cpanel?cpanel_jsonapi_user=cr&cpanel_jsonapi_apiversion=2&cpanel_jsonapi_module=EmailTrack&cpanel_jsonapi_func=search&success=1&defer=1&failure=1&inprogress=1&api2_filter=1&api2_filter_column=actionunixtime&api2_filter_term=1605210441&api2_filter_type=eq
When running this I'm getting many results from the EmailTrack that do not include that value, I tried filtering a couple other fields such as size and sendunixtime, but neither of those worked. However, using the filter on recipient field did work, what gives? Is there something I'm doing wrong or is this field not filterable, the documentation doesn't appear to have anything related to not being able to filter on this field.