Planned date & duration do not update

Hi,

Just use the "fixed duration" planning mode.
 

You are welcome !

You can impact the planning by playing with the different planning modes.respecting constraints you gave.
In your case :
you can smooth the load between two dates: the planning will not necessarily be correct from day to day but it will respect your wishes.
You can use the fixed duration even if the follow-up with the work done on it for the planification is not very judicious (we cannot steer an activity at the same time by the load and by the duration if it is not by adjusting one to the other manually)
you can use the manual schedule by half day

Incidents are registered by tickets . Tickets can be linked to a "planning activity" dedicated for their resolution.