joined:Sept 26, 2018
Visits to your website from links on Facebook may now have a parameter added to the destination URL. This parameter is added by Facebook and starts with fbclid
I have noticed that this parameter when added to a URL triggers a visit from Google Mediapartners bot, presumably it thinks the page is different than without the parameter, and thus Adsense may not show adverts on the page until subsequent visits to the URL with the same unique parameter. You may be missing out on valuable Adsense impressions because of this.
In my server config file I now remove the facebook fbclid parameter from all URLs, unless it's from the facebookexternalhit bot.