Gantt display wrong in the duration bar

Hello,

First of all, I want to let you know that you are working on a version that has never been tagged stable. First, consider upgrading to version 9.0.6.
Maybe the problem will be solved after this.

If not, remember to check if your activity is not paused, it cannot be seen in your screenshot.
Otherwise, check the capacity of your resource, if its FTE is> = 5 then it will do what it was assigned to in 1 working day.

Do not hesitate to come back to us if the problem persists!
Good continuation