Interesting. I've never seen that before. And that's not how my charging screen on my Note 8 looks either. I did some searching though and found mention to a feature that allows third party applications to display advertisements on your screen when it is charging (see this). If that's at play here then this advertisement came from an application that was installed. From the site on which I found this information: You can find out if an app is a culprit in serving ads this way by heading to Settings – Developer Options – Running Services, and tapping each app individually. Inside you may find an app running a service called “ChargeLockerService”. This is the bit that could be serving you ads – you’ll have to switch the app off or uninstall, then reinstall to check.
... View more