[Plugin: Advertwhirl Advertising Manager and Ad Rotator] Default Adsense Ad showing occasionally

I’m setting up a site using this plugin. I am using local ads only at this point as I test it out.

I have noticed that occasionally a Google Adsense leaderboard banner will display in my ad slots. When I refresh it goes away.

Why is this happening?

My test site: https://valencia.directrouter.com/~greatame/

https://www.ads-software.com/extend/plugins/advertwhirl/