Currently, on project timelines, task dates will be calculated (when using constraints like ASAP) by taking the assignee's availability to acquire duration and then adding on any predecessor dates. Even if the predecessor pushes the start date to after the assignee is back in the office and available, it will still use the originally calculated duration to set the due date. Unfortunately, this means that tasks can be unnecessarily delayed or pushed out.
For example, to use an extreme case, If an assignee on task with a 2 day duration has 2 weeks off, their task duration will be calculated as 2 weeks plus the 2 days. If that task, however, is dependent on a predecessor task, current calculations will add that predecessor task duration to the total.
Where it gets tricky is if that predecessor task was 2 weeks long and now the assignee is back from vacation and available, it does NOT adjust the calculation, and still assumes 2 weeks and 2 days, pushing the task out 2 additional weeks unnecessarily.
A WF engineer has confirmed that this is how the calculation works and it is as designed.
I'd like to recommend that calculation be refactored to properly take into consideration the PTO AFTER taking into consideration the predecessor lag time, since the time off no longer applies and shouldn't be added into the duration.
This would be a correction for the current calculation.