A major app developer has been found sneaking adware into over 200 Android apps listed on the Google Play Store. The adware, named BeiTaAd, would only present adverts after at least 24 hours from an affected app being first opened, tricking people into believing other apps were at fault.
https://www.notebookcheck.net/BeiTaAd-adware-found-in-over-200-Android-apps-on-the-Google-Play-Store.423097.0.html