There is a change with the version 4.4.5 of JIRA which makes cloning a task with sub-tasks somewhat troublesome. In the previous version 4.0.2 the cloned subtasks would not have the leading "CLONE -" applied to them, but only the parent task. Now the sub-tasks get this and if you don't edit the description and continue to clone the parent tasks the sub-tasks description starts to look something like this: CLONE - CLONE - CLONE
This might be somewhat annoying and not helpful. So I think having only one instance of the word CLONE would be sufficient even if I choose to clone a clone.