Roku TVs are a bit of a mystery. While Roku provides the operating system, they don't build and sell the TVs. Each manufacturer can make changes in hardware or software that make some channels problematic. For example, I have two Roku TVs. One is a 43" Sharp 4K Roku TV, and it does just fine with everything I've tried with it. My other one is an Insignia 24" 720p set. It is noticeably much lower on processing power, and I wouldn't be surprised if it had issues with CBS AA. While I do subscribe to CBS, I've only watched it on my Shield or Ultra players.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.