Skill bonus active for null

Hi everyone,
Does enyone know if the message “Skill bonus active for null” actually means that bonus is not active or it will perish in less than a day?
I am a little confused because if I remember correctly, the number +4 was greyed before we completed the task. I was expecting it will return to that state.

during the noght the task was completed (so around 8 hours from my post) and the task now shows that bonus will be active for 5 days. That doesn’t make sense. It should be 7 days or at least 6 days.