Explanation
Returns Item1 only as EnableCrossPartitionQuery property to False. If EnableCrossPartitionQuery property is set to true, it will return Item1, Item2, and Item3.
Reference:
https://docs.microsoft.com/en-us/azure/cosmos-db/sql-query-where
https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.documents.client.feedoptions.enablecrosspartitionqu