Flickering white distortions on my TV screen whenever the picture is in motion. Shows up worst against dark color backgrounds. What could be causing this?

Just noticed this today when I started watching March Madness. TV has been working fine up until now, no impacts of any kind. Is this a hardware issue? The lines show up both on antenna signal and my streaming app. For still pictures they don't show up much but with a fast-moving broadcast it's extremely apparent.