We have previously had good results using the CloudAppEvents table in Advanced Hunting, filtering on the ActionType "FileUploadedToCloud". Historically this query produced hundreds of results per day in our environment.
Over the past month or two, the number of results has dropped significantly, despite no changes to the query or to the way we would expect users to interact with cloud storage services. We are receiving other cloud events from these devices, so I don't think there is a telemetry issue.
Is anyone aware of recent changes, or have any other ideas?