VBS Defaulting Works for Update Position but Not for Correct Position

I have implemented a VBS defaulting expression to ensure that Standard Working Hours (SWH) is populated from the selected Job whenever the Job is changed under Position Details:

[[$fields.positionsV2.job[0].StandardWorkingHours.$value()!=null?$fields.positionsV2.job[0].StandardWorkingHours.$value():$fields.positionsV2.job.StandardWorkingHours.$value()]]

This works as expected in position-related transactions, such as Promote and Change Position, where the Standard Working Hours field is updated correctly after changing the Job.

However, I am seeing inconsistent behavior on the Positions page, which provides the three actions Correct, Update, and Duplicate. Although all three actions open the same VBS page, the behavior differs: