This feature is totally broken and should just be removed.
I honestly don't know what convenience it adds, even if it were to actually work properly. If a network has multiple Roku devices, why do you assume we want to connect to the last one we used?
On the contrary, it's a major inconvenience to have to force close the app each time, because there's no other way to cancel it and the developers didn't bother to put in any kind of time out scenario. It doesn't even look to see if you're still on the same network as the device before it does this.
NOTE: I've tested on multiple Android devices and the app does it on every single one.
And yes, the device and the Roku are both on the same network. They're even on the same network band. PNP is allowed on my router, if that even matters. I've even tried assigning a static IP to the Roku device and the device the app is on.
Either give us an option to disable this feature or just remove it and throw us back to the main menu like the old Roku app used to do.