Confluence Task Report Macro - Cannot change task states

[Paul]

Users are reporting they are unable to change status of tasks on pages using the Task Status Macro

When changing the status of a task the server log file includes the error :-

[atlassian.confluence.event.ConfluenceEventDispatcher] run there wan an exception thrown when trying to dispatch event [ConfluenceTaskUpdateEvent

further down the stack trace is a NullPointerException thrown in :-

com.atlassian.mywork.model.TaskBuilder.java:39

We are running Confluence Server Data Centre Version 6.13.4 

Has anybody else experienced this problem?

Many Thanks

Paul.

[why]

I'm having the exact same problem in Confluence Server 6.13.4

The task status can only be changed by clicking on it twice, the first time often fails.