I assume that if the popups are being generated from an app that you have allowed, and given permissions to, it is not then Malware so Malwarebytes will not detect it. Again, neither is it a virus - I have run AVG Antivirus Pro and also Malwarebytes and neither reported any issues. To try and solve the issue I have spent a few minutes uninstalling any app I don't recognise and any app that I have recently installed. I'm testing now but so far, so good. It was strange that when I clicked on the Uber app to uninstall it the games popup started immediately - I'm not pointing the finger at Uber but it was a bit suspicious.