Hi.
I have the same problem with two Ultra LT (4662RW).
Both Ultra LT are running now on latest available Software versions.
One on 13.1.4 and the second on 14.0.
I tried also on earlier Software versions, but it I was never able to use Screen Mirroring.
I tried with three phones, M31, A34 and A54. With no one of them I get it running.
I am able to see and to select the Roku device on my phone to start the screen mirroring, but after 10 or 15 seconds, I get the message on my phone that I should restart the device and try it again.
Except these two Ultra LT devices, I have two Roku Express 4K+ devices as well.
With that both Express 4K+ debices, the screen mirroring is working with all 3 phones I have. It works very well and stable.
