Tried simulating this issue with the patch against the tests testrunner has - run log. Observation from one the failures:
02:02:45.192-07:00 - 02:08:02.883-07:00 : During this period, GoCB returned "no access" error
02:08:05.126-07:00 - 02:08:06.383-07:00 : During this period, GoCB returned "operation has timed out"
02:08:07.633-07:00 - 02:08:27.308-07:00 : During this period, GoCB returned "temporary failure occurred, try again later"
02:08:28.308-07:00 - 02:08:51.810-07:00 : And finally it again started throwing "operation has timed out"
Seems like GoCB gets somewhat screwed up in some cases when a KV node is recovered post failover. If I above it again, will file a JIRA against SDK.