updated_at not getting changed for custom attributes in API V2

After updating a person custom_attributes, the updated_at timestamp does not change.

its only getting udpated for some specific fields. Custom attributes attached to the profile must also be included.

when we change a custom attribute on a person, he is not included in the API V2 get persons with udpate_at.gt, as updated_at is not touched. we can see that by getting a person by id in api.

how can we include the custom attributes which are attached directly to the profile to be considered for change?

Thanks