Workflow feature build fails

java.lang.RuntimeException: com.nuxeo.studio.core.api.exception.StudioException: Failed to build feature with type 'workflow' and id 'DIWorkflow'
	at com.nuxeo.studio.core.buildservices.BuildServiceImpl.build(BuildServiceImpl.java:126) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.VersionServiceImpl.createAndPublishSnapshot(VersionServiceImpl.java:224) ~[nuxeo-studio-core-4.0.4.jar:?]
	at com.nuxeo.studio.core.build.StudioPackageBuilder.build(StudioPackageBuilder.java:79) ~[nuxeo-studio-core-4.0.4.jar:?]
	at com.nuxeo.studio.core.build.StudioPackageBuilder.buildAdminCenter(StudioPackageBuilder.java:56) ~[nuxeo-studio-core-4.0.4.jar:?]
	at com.nuxeo.studio.servlet.StudioServlet.doBuildAndDownloadProject(StudioServlet.java:196) [nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.servlet.StudioServlet.handleGet(StudioServlet.java:149) [nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.servlet.StudioServlet.doGet(StudioServlet.java:124) [nuxeo-studio-ui-4.0.4.jar:?]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [servlet-api-9.0.36.jar:?]
	at com.nuxeo.studio.servlet.StudioServlet.service(StudioServlet.java:105) [nuxeo-studio-ui-4.0.4.jar:?]
  ...
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-coyote-9.0.36.jar:9.0.36]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-coyote-9.0.36.jar:9.0.36]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-coyote-9.0.36.jar:9.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-coyote-9.0.36.jar:9.0.36]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-coyote-9.0.36.jar:9.0.36]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_252]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_252]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util-9.0.36.jar:9.0.36]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_252]
Caused by: com.nuxeo.studio.core.api.exception.StudioException: Failed to build feature with type 'workflow' and id 'DIWorkflow'
	at com.nuxeo.studio.core.buildservices.BuildServiceImpl.doBuild(BuildServiceImpl.java:149) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.buildservices.BuildServiceImpl.build(BuildServiceImpl.java:107) ~[nuxeo-studio-ui-4.0.4.jar:?]
	... 88 more
Caused by: org.nuxeo.ecm.core.api.model.PropertyConversionException: Property Conversion failed from class java.lang.String to class [Ljava.lang.Object;: var_DIWorkflow-20181203162448870-accept-reject-task:tiers2
	at org.nuxeo.ecm.core.api.model.impl.ArrayProperty.normalize(ArrayProperty.java:110) ~[nuxeo-core-api-10.10-HF29.jar:?]
	at org.nuxeo.ecm.core.api.model.impl.AbstractProperty.setValue(AbstractProperty.java:418) ~[nuxeo-core-api-10.10-HF29.jar:?]
	at org.nuxeo.ecm.core.api.model.impl.ArrayProperty.setValue(ArrayProperty.java:68) ~[nuxeo-core-api-10.10-HF29.jar:?]
	at org.nuxeo.ecm.core.api.model.impl.AbstractProperty.setValue(AbstractProperty.java:465) ~[nuxeo-core-api-10.10-HF29.jar:?]
	at org.nuxeo.ecm.core.api.impl.DataModelImpl.setData(DataModelImpl.java:101) ~[nuxeo-core-api-10.10-HF29.jar:?]
	at com.nuxeo.studio.core.builders.workflow.RouteNodeDetachedDocumentModel.setProperty(RouteNodeDetachedDocumentModel.java:245) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.builders.workflow.RouteNodeDetachedDocumentModel.setDocumentProperties(RouteNodeDetachedDocumentModel.java:106) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.builders.WorkflowFeatureBuilder.nodeToDeatchedDocumentModel(WorkflowFeatureBuilder.java:161) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.builders.WorkflowFeatureBuilder.routeToDetachedDocumentModel(WorkflowFeatureBuilder.java:153) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.builders.WorkflowFeatureBuilder.build(WorkflowFeatureBuilder.java:113) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.builders.WorkflowFeatureBuilder.build(WorkflowFeatureBuilder.java:73) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.buildservices.BuildServiceImpl.doBuild(BuildServiceImpl.java:146) ~[nuxeo-studio-ui-4.0.4.jar:?]
	at com.nuxeo.studio.core.buildservices.BuildServiceImpl.build(BuildServiceImpl.java:107) ~[nuxeo-studio-ui-4.0.4.jar:?]
	... 88 more