Consider it more a usability isse then. 
I would expect an error message or something if there is no batch task to the project. At the moment the error is silently ignored if I don't enter a batch task name ot there is none. Next time I open the configuration, the batch task name is magically set to the first
batch taks - but this appears to be for the GUI only. And it becomes more confusing, with the build error ""ERROR: No such task exists: . Perhaps you meant foo". Becuase if I look at the configuration GUI, "foo" is written there.
you have to save your new batch task, then configure the project again and select both the project name and the particular task to execute in the post-build step.. sounds like you had the project name, but not the particular task. so I'm not really seeing what the bug is here.. ?