Our setup is similar to @sandrahill where only select metafields are mapped from NetSuite in product flows. This is very intentional. Other metafields are managed directly in Shopify by web staff. And other metafields are created/edited by apps.
I agree the documentation should be updated to flag this issue (or even an emergency email to all possibly impacted customers) because it's a critical issue to consider when switching to the new flows and a major change to the functionality. If the issue can not be fixed, our Celigo integration would become unusable and need to be disconnected before the April 1 deadline.
@nileshkumar Please consider making a fix available sooner than the third week of March. Or extend the April 1 migration deadline. A one week migration window is not enough time.