Task uncompletion is not synced

[tbabej]

When I have a task in my vimwiki file, which was marked completed upon loading:

* [X] Next random thing (2014-11-21 00:00) #785e10ef-5f7d-44b8-83c6-f7be496b94aa 

and I undo the task completion, the change is not propagated to the taskwarrior:

$ task 785e10ef-5f7d-44b8-83c6-f7be496b94aa info | grep Status
Status        Completed

Upon reloading the file, I can see that task is again showing up as completed in the wiki file (which is correct, since that is performed by the vimwiki-tasks sync upon loading the file).