How are you waking your Roku? You should only ever press the Home or Back buttons to wake it. If you press the OK button (or some of the other transport buttons), you might be clicking on a hotspot on an ad, and that would certainly open some strange page. My Ultra always opens on the Home screen using the Home button to wake it.
Quite often I use the the handsfree voice remote and say „Roku tv on“. Or I use the power button on the remote.
Anyway this issue wasn’t always the case. It’s something that’s been happening for a few months.
