Position Synchronization issue set to No - causing issues

We have observed an issue with Position synchronization on our project. The clients are already live with ERP and we are implementing HCM now. Due to this, the approach we are following is to enable Position sync on the Enterprise after we complete the Assignment data migration into the environment. The issue with that is all the assignments that have been loaded into the system have 'Synchronise from Position' marked as No. So, the top of the stack record for all employees has the 'Synchronize from Position' flag as N. This is causing any position updates to not sync into