Due to the global impact of COVID-19, Facebook working with their partners to send home all contract workers who perform content and ad review, until further notice.
Facebook will remain committed to keeping platform safe and minimizing disruptions for businesses. Ad reviews are expected to take longer than usual, and this may cause delayed ad delivery. Appeals may also be reduced or experience slower response times.
When new ads are submitted they require review. Also, when ads are edited, such as changing the text, targeting or destination landing page, that will also cause a new review to occur.
Facebook said to consider the following:
Only change the budget or start/end date for an existing ad so it doesn’t trigger a new review.
If your ads are performing well, consider extending the delivery period for those ads instead of creating new ads.
Ref:https://www.facebook.com/business/help/285854632398488
