I see nobody has replied in 12 hours. I expect this is because yours is a really unusual problem and so far nobody has any suggestions.
I know I have two Roku sticks and one Roku tv all connected to the same network via WiFi and I've never experienced what you describe.
What router model are you using?
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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