Tablo causes tv to go blank

I have an attena in my garage. I am using the newer roku’s. With the attena is attached to my tablo, the tv screen goes blank with no picture or sound for about 3 seconds. When I connect the attena directly to my tv everything is fine.
Any idea why the tablo duel box is causing my screen to go blank?

Is this a random event or a once in awhile or only when I first start playing a recording/Live Tv.

What is your Roku video resolution setting?

I experienced this. Not long after getting the Tablo and only using the Tablo. My troubleshooting was a little different and took me a different path and to my solution. The Tablo was in a different room than the TV and Roku. I rebooted the Roku as it was right there and it was fixed only to return later, once again only when using the Tablo. I don’t remember exactly what I did, and though the Tablo was in the list of possibilities I put it last. What I ended up messing with was the HDR settings between the TV and the Roku. I think I disabled HDR on the TV. Having run from hurricane Michael neither the TV or the Roku are within possession to tell you which one. Forgive me, back into obscurity.