I think your issue is the original bloks display. I had the same issue with my 2017 vado 3 in the rain. The bike would turn on by itself then I coulded turn it off without taking the battery out. The display mount was changed to a upgraded bloks mount and this issue went away. My bike has since been upgraded to the latest display so it can be connected to the mission control app. I have nearly done 10000km on my bike in all weather and in all power modes. I would get your display mount changed or if you can upgrade to the latest version display. Specialized were upgrading the display on 2017 bikes under warranty but not sure how this effects your bike being second hand. Hope this helps!