There are several things that can cause the remaining time to not show the expected value
Normally, the Remaining time should be the Estimated time minus the Actual time.
If something is unclear: Compare the changes to Actual and Remaining time in the issue history with the work logs in the work log section.
Normally, adding a work log to an issue adds the worklog time to the 'Actual time' field, and subtract the worklog time from the 'Remaining time' field.
In some cases the issue history and the work log section can differ from each other:
- Issue had its Actual and Remaining values manually edited with no work log added.
- Some work logs does not seen to have checked the "update remaining time" checkbox, as they only update the actual time, and not the remaining time.
- Sometimes it seems a work log has been edited after being added to the issue, and it may be that the "update remaining time" checkbox is checked in the edit but not in the original (or vice versa). Ex. first adding a 3 hour work log (actual time +3, remaining time not updated) and then editing the work log to 2.5 hr, and this time the checkbox is checked (3h->2.5h: actual time -0.5 h, remaining time +0.5 h)
- Remaining time can not get negative, but Actual time can be more than Estimated time. This can cause problems if work logs are first applied in excess of the remaining time, and then removed. (example: (Est=16, Act=12, Rem=4). This is OK. Now we first add a work log of 5h. (Est=16, Act=17, Rem=0), and then remove it (Est=16, Act=12, Rem=5). This way an extra hour is added, and the time math is no longer correct.