What is Facebook Test Traffic?
When Facebook reviews an ad it also reviews the landing page. Sometimes this can be a few sessions but in others, there can be an influx of low-quality traffic on the day the ad is reviewed.
You can see if this is the case by breaking down your campaign traffic by location or region in Google Analytics.
Facebook goes through this step regardless if an ad was updated in the Ads Manager or using EasyAutoTagging. We have not seen any consistent patterns across accounts and for most users test traffic coming from Facebook is low.