Google Workspace Reporting Watch Request Auto Deletion

Hi,

We are using the following API for getting google drive reports:
https://developers.google.com/admin-sdk/reports/v1/guides/push
i.e

POST https://admin.googleapis.com/admin/reports/v1/activity/users/all/applications/drive/watch

We have noticed that notifications are intermittently stopped by Google drive even when the subscription is not expired.
We have a single service account which is being used by multiple organizations.

We have observed as of late that we stop receiving webhooks after the first few notifications and there is no way to dig deep further.

We have also noticed that the webhook gets deleted as the resourceId is no longer unique when we try to hit the api with the same channelId as otherwise we would get the channelIdNotUnique error.

We would like to understand are there any limitations of using report/watch api?

We have also noticed that when making this API call, occasionally we get an ACCESS_TOKEN_INSUFFICIENT error with a token that has the sufficient scopes.