While a function app is stopped in the portal (for maintenance, deployment etc) any web requests are rejected with "Error 403 - This web app is stopped."
Since the event grid retry policy does not retry on 403, any events published to the function app via EventGridTrigger during this time will be instantly dropped or dead-lettered.
Azure event grid should retry on HTTP 403 or the function app should return "Error 503 - Service unavailable" while stopped.
While a function app is stopped in the portal (for maintenance, deployment etc) any web requests are rejected with "Error 403 - This web app is stopped."
Since the event grid retry policy does not retry on 403, any events published to the function app via EventGridTrigger during this time will be instantly dropped or dead-lettered.
Azure event grid should retry on HTTP 403 or the function app should return "Error 503 - Service unavailable" while stopped.