Azure Cosmos DB Mongodb $t and $v
(If someone can make this a comment instead of an answer, it would be appreciated)
I'm getting the same thing. It looks like Microsoft gave an answer here as to why it happens: http://answers.flyppdevportal.com/MVC/Post/Thread/e0ffdbcd-0b43-4cd5-9d21-1a95ce0279dd?category=azuredocumentdb
The incorrect format is a result of intermixing the Cosmos DB: MongoDB API with the Cosmos DB: DocumentDB API.
It's not very clear to me though why those two are intermixed since MongoDb maintains the MongoDB API NuGet.
This is happening because one of your Cosmos DB MOngoDB API accoutn is older than the other - older one uses JSON schema (used by SQL API as well), while newer uses more versatile (and MongoDB compliant) BSON schema. You just need to request the conversion of the account to a new schema by emailing askcosmosmongoapi@microsoft.com