If you awning is a Solera SmartArm does it have the optional IR sensor? If so and the light button is in "Auto" the lights will come on when motion is detected.
I've noticed on my 2018 3011DSF with a Solera SmartArm if I turn on the awning light with OneControl and off with the outside awning button the OneControl status continues to show "on" although the light is actually off, and vice-versa. I haven't had the problem you've described but maybe OneControl periodically polls connected devices and is turning the awning light back on. The preceding is just a WAG
EDIT: Just re-read your post and you said the coach power was off so I just tried turning on my awning via OneControl and off with the awning button and when I turned off the coach power the awning light came on. I don't have a definitive answer but maybe your issue is due to the way OneControl interacts with a manually controllable device.