Intermittent ServiceUnavailable when requesting unknown view

When running view queries against an unknown view design document and view name, the server intermittently resets the connection. This occurs intermittently locally, against a number of server versions but consistently when running on Jenkins CI job, which uses 4.5.0.

This issue was discovered when changing from submitting queries using a GET to POST with the keys value in the body as a JSON object.

After some investigation comparing HTTP requests made by .NET with LCB and Java, there doesn't seem to be anything untoward. Once noticeable difference is that .NET always includes the Connection: Keep-Alive header, where the others do not but disabling this doesn't seem to impact behaviour.

Verified when running against server versions 4.5.1 and 4.6.3 but not 5.0.