As per the following release notes, the view problem is resolved with the workaround (web.config parameter change)
Couchbase .NET incompatibility
An incompatibility between Microsoft Framework 4.0 or earlier, the Couchbase .NET SDK 1.3.7 or earlier, and Couchbase Server 3.0 has been identified where the URL generated for a View operation on the Couchbase bucket is improperly encoded. This causes view requests to fail with the following message in the body:
"Design document not found, body:
The affected Microsoft .NET versions are 4.0 or earlier, Couchbase .NET SDK 1.3.7 or earlier, and Couchbase Server 3.0 (including Beta) is >= 3.0.
Microsoft .NET version 4.5 changes the way Uri.ToString handles its Unicode encoding, which resolves the issue. In this case, clients running on this version or higher of the CLR are not impacted. Additionally, Couchbase Server 2.5 and lower are not impacted.
In addition to the patch released with Couchbase .NET SDK version 1.3.8, add the following element to your App.Config orWeb.Config to enable support for all SDK and Server versions:
Customers who are not ready or cannot upgrade their Couchbase .NET SDKs to 1.3.8 or greater are strongly advised to add this element to their deployments if they intend to use the Couchbase .NET SDK with Couchbase Server 3.0 or greater.