YT Tracker lists duration of the video along with many useful metrics. When the video duration is less than a hour, it will be in mm:ss
format. It won't have the hour offset. To get the hour offset in the duration column, you can select Extensions → YT Tracker → Settings → Customization, check Add hour offset to duration and save.
For instance, if the video duration is 6 minutes and 36 seconds, you will see 00:06:36 in the duration column against that video.