Atea rounds the time to minutes, but always by default.
If a user has many small tasks and starts/stops the counter frequently, after a while it will miss many minutes.
Atea should round the time up when more then 29 seconds have passed.
This would balance the minutes rounded by default and provide more accurate time tracking.
This was in the back of my head when I wrote the timing code but dismissed with a simple "ah it's gonna be ok" :)
You're right though, tagging this as a bug.