Having read the answer in this previous Jira suggestion, I would like to offer a suggestion of at least a VISUAL INDICATOR that a Task or Sub-task has time logged against it, as you view it in the parent Story. Some little distinctive icon would help to determine if ANY time is logged so far on a task or sub-task, without having to open each one.

Currently, when on a Story, and you are analyzing the progress, you cannot easily see whether time is already logged on a Task or sub-task, and it would be very help in making decisions about that Story vis a vis it's current Sprint and expectations to get it done, or move to another Sprint.