Test failed with

MongoDB.DriverOnlineTests.MongoCollectionTests.TestReIndex:
Expected string length 29 but was 28. Strings differ at index 22.
Expected: "Duplicate element name: 'ok'."
But was: "Duplicate element name 'ok'."
---------------------------------^

at

at MongoDB.DriverOnlineTests.MongoCollectionTests.TestReIndex() in C:\source\mongo-csharp-driver\DriverOnlineTests\Core\MongoCollectionTests.cs:line 940