Providing this information for anyone who doesn't know. If you truncate/append your webhook enabled hosted feature service, it is very likely that the first edit post-append will be reported by the webhook as an empty edit. See BUG-000145215
If this impacts you please subscribe to the BUG and/or call your technical support rep. This wasn't deemed important enough to address in this latest AGOL update. It needs more traction.
Example of what is returned by webhook:
"edits": [
{
"id": 0,
"features": {
"adds": [],
"updates": [],
"deleteIds": []
}
}
]