Project Server PSI computes different schedule than MS Project Professional does on tasks with lagging RRS feed

  • Question

  • In our setup Project Server 2010 we update some project data using PSI. It all works fine besides some tasks that have constraint Start After Finish with a delay (lag) (number of days). I reproduced this behavior with just 4 tasks. If we update tasks via Project Professional it works but

    if we update via PSI the lagging does not work. The lagged tasks begin on the same date as the predecessor ends.   

    The setup is easy

    task 1 - begins as late as possible ( the rest of the tasks begins as soon as possible)

    task 2 - depends on task 1 with lag of 10 days

    task 3 - depends on 2 and is constraint to start on some date. (this constraint date is a parameter that PSI (Project Professional) changes 

    IF we change the constraint on task 3 in Professional then task 1 and 2 move along. If we change it via PSI , task 2 is loosing the lag and will start when task 1 finishes. 

    Any idea? 

    Seems to be a bug in PSI engine , that produces different results from Professional

    From Project Techcenter

    Tuesday, November 8, 2016 6:32 PM