I have a Roku Premiere+ (4630 series) and for the last few days, I've had to reboot the device every day in order to get it to work properly.
When I turn the TV on and use the Roku, the device/interface is extremely sluggish. If I try and start watching a program, it might work for a little bit before acting up or it might instantly start acting up. Video will pause, buffer, the screen will go black, frames will stutter, etc.
Once I reboot the Roku, then it behaves perfectly, until I turn the TV off and come back to it the next day and it's back to being sluggish and constantly buffering.
I have the Roku connect to a receiver that is connected to the TV. I've made no recent changes to the Roku or the set-up so I'm not sure what is causing this issue.