Matt,
Last night I filed another, more subtle, problem that I was having with the latest versions of the client library:
https://www.couchbase.com/forums/t/issue-with-merging-queries-with-cb-4-6-java-2-3-5/11031
When I wind this example back to the old versions, I get an exception thrown:
com.couchbase.client.core.RequestCancelledException: Request cancelled in-flight.
I would guess that this is what was happening in my real code, but I was failing to catch the exception, so it just looked like a ‘hang’ until timeout.
Hopefully that helps somewhat.