Couches client illegale exception with 2.1.2 version

Couchbase Server 3.0.1
Java client 2.1.2

We have been facing this issue on below code -

public UserDocument getUserByUserName(String userName) {
		UserDocument userDocument = null;
		if (userName == null) {
			return null;
		}
		ViewResult result = bucket.query(ViewQuery
				.from(DesignDocumentEnum.USERNAME_DESIGN_DOC.getName(),
						ViewEnum.BY_USERNAME.getName()).key(userName).limit(1));
		if (!result.success()) {
			return null;
		}
		List<ViewRow> allRows = result.allRows();
		for (ViewRow row : allRows) {
			JsonDocument userDocumentJson = row.document();
			userDocument = gson.fromJson(
					userDocumentJson.content() != null ? userDocumentJson
							.content().toString() : null, UserDocument.class);
			break;
		}
		return userDocument;
	}

We are not able to figure out why this happening. Based on our investigation this is pretty random,

! java.lang.IllegalStateException: The Content of this Observable is already released. Subscribe earlier or tune the CouchbaseEnvironment#autoreleaseAfter() setting.
! at com.couchbase.client.core.utils.UnicastAutoReleaseSubject$OnSubscribeAction.call(UnicastAutoReleaseSubject.java:230) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at com.couchbase.client.core.utils.UnicastAutoReleaseSubject$OnSubscribeAction.call(UnicastAutoReleaseSubject.java:202) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:145) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:137) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:145) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:137) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:145) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:137) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:145) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:137) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:145) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable$1.call(Observable.java:137) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
! at rx.Observable.unsafeSubscribe(Observable.java:7304) ~[pgweb-usermanagement-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]

did you get an answer to this questions