Depending upon which version of the .NET client you are using, this may be a bug. That's the bad news. The good news it's fixed, but not released (yet):
- http://www.couchbase.com/issues/browse/NCBC-416
- List https://github.com/couchbase/couchbase-net-client/commit/fc92b9e0e71e60fcba7e6f92eab337160af0cae4
This will be released the first week of May (version 1.3.5). The bug was introduced in the 1.3.3 release.