We want to sincerely apologize for the inconvenience this has caused.
A cloud storage service provider, like Amazon Drive, should never, ever return an empty list of items with a 200 OK response unless the items are actually not there. There is a required trust in the sync relationship that the service provider is providing accurate information. The cloud service is considered the authoritative source for the linked storage and when changes are made on the remote they need to be synced to local, as per the sync relationship. In this case Amazon Drive returned false information, which odrive then acted on.
The team is discussing what steps we can take to guard against this type of major service provider failure in the future.