I am experiencing a similar issue with my 350. I posted the following as a question today.
My remote 350 displays live TV beautifully, even on HD mode, from my Spectrum cable provider using their Cisco DVR. Not a single hitch or pixilation.
HOWEVER, try to playback a DVR recorded show, the stream becomes unwatchable.
What is different about the signal from the Cisco DVR that is causing the SlingBox so much trouble?
Has anyone overcome this issue?
I see similar issues on the forums posted for previous YEARS, yet no obvious solutions.
Thanks for your support!
Did you ever find a resolution or support?