Let’s recap on the tradeoffs between the various approaches:

Prospective Validation

This is potentially the highest cost, especially if you’re already planning on dumping anything produced, but absolutely the lowest risk.

No product is distributed or even planned for distribution.

All issues found during validation are corrected and so the risk of distributing nonconforming product is lowest.

For quarantined product produced with the intent to be distributed after passing validation, extra actions are needed to properly control the product, but you don’t have to worry about recalls.

Concurrent Validation

This is a balance between cost and risk.

If no issues are found during validation, the product can continue to be distributed with reasonable assurance that none of the product will be found nonconforming.

If issues ARE found during validation, previously distributed product must be addressed, although concurrent validation batch acceptance criteria should already be designed to mitigate risk.

Retrospective

By far the biggest risk.

Should problems arise during validation, as noted, this could result in extensive recalls.

Worse, it may require attempting to notify past users of products.