failedJobRetryTimeCycle has wrong format:R5/PT5S

1 
<serviceTask id="downloadDocuments"
			name="Download the documents"
			flowable:async="true"
			flowable:delegateExpression="${flowableFileDownloadServiceImpl}">
			<extensionElements>
				<flowable:failedJobRetryTimeCycle>R5/PT5S
				</flowable:failedJobRetryTimeCycle>
			</extensionElements>
		</serviceTask>

im using spring boot and flowable 6.5.0
im getting exception as

Exception in thread “SimpleAsyncTaskExecutor-1” Exception in thread “SimpleAsyncTaskExecutor-1” org.flowable.common.engine.api.FlowableException: failedJobRetryTimeCycle has wrong format:R5/PT5S

	at org.flowable.engine.impl.cmd.JobRetryCmd.execute(JobRetryCmd.java:127)
	at org.flowable.engine.impl.interceptor.CommandInvoker$1.run(CommandInvoker.java:51)
	at org.flowable.engine.impl.interceptor.CommandInvoker.executeOperation(CommandInvoker.java:93)
	at org.flowable.engine.impl.interceptor.CommandInvoker.executeOperations(CommandInvoker.java:72)
	at org.flowable.engine.impl.interceptor.CommandInvoker.execute(CommandInvoker.java:56)