I have a similar problem, except the audio goes out too and it doesn't happen on a regular "every 2 seconds" basis - the time outs vary, but occur continuously. But the pictures goes out on every on every streaming channel. I.e., I have Roku Ultra and I stream YouTubeTV, Pluto, and Acorn; the issue occurs in all of them. I have a Vizio TV and all of my softwares on all channels, Roku, and the TV are up-to-date. My internet provider denies it is there system, so that kind of leaves Roku. Can we get any help at all? Thank!
Thanks for reaching out here.
Based on the behavior you described, this is most likely an issue with either the HDMI cable you are using, or the HDMI port connection to the TV. 4K Roku devices require the use of a high-speed, HDCP 2.2 certified HDMI cable in order to work correctly. This type of issue may also occur if a connection is loose, an HDMI port or connector is dirty or dusty, etc.
I would recommend replacing your HDMI cable with a new HDCP 2.2 certified cable, and try connecting your device to a different HDMI port on the TV to see if this resolves the issue. I would also double check that you've disabled 'Auto-adjust display refresh rate' in Settings>System>Advanced system settings>Advanced display settings.
Keep us posted from there!
Thanks,
Tanner