NPE rendering work logged email with '0m'

The below occurred after logging 0m to a task:

An error occurred whilst rendering this message. Please contact the administrators, and inform them of this bug.

Details:
-------
org.apache.velocity.exception.MethodInvocationException: Invocation of method 'indentToChangelog' in class com.atlassian.jira.util.JiraVelocityHelper threw exception class java.lang.NullPointerException : null
at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:246)
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:172)
at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:114)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.app.VelocityEngine.evaluate(VelocityEngine.java:316)
at org.apache.velocity.app.VelocityEngine.evaluate(VelocityEngine.java:210)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBodyForContent(DefaultVelocityManager.java:142)
at com.atlassian.jira.mail.MailingListCompiler.addMailsToQueue(MailingListCompiler.java:224)
at com.atlassian.jira.mail.MailingListCompiler.sendLists(MailingListCompiler.java:135)
at com.atlassian.jira.mail.MailingListCompiler.sendLists(MailingListCompiler.java:88)
at com.atlassian.jira.mail.IssueMailQueueItem.send(IssueMailQueueItem.java:167)
at com.atlassian.mail.queue.MailQueueImpl.sendBuffer(MailQueueImpl.java:68)
at com.atlassian.jira.service.services.mail.MailQueueService.run(MailQueueService.java:23)
at com.atlassian.jira.service.JiraServiceContainerImpl.run(JiraServiceContainerImpl.java:61)
at com.atlassian.jira.service.ServiceRunner.execute(ServiceRunner.java:48)
at org.quartz.core.JobRunShell.run(JobRunShell.java:191)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:516)